CMeterial New

Chapter 1 Introduction to C Programming Introduction: Lower level language Higher level language Object Oriented Language Feature of C Character set in C Structure of a C program Basic Input / output functions Standard output function printf() statement Syntax Format modifiers putchar() statement Escape sequence C tokens Constants Integer constants Floating-point constants Character constants String constants Symbolic constants Identifiers Declaration of identifiers Operators Unary operator Binary operator Turnary operator

Chapter 2 Introduction to standard input function and operators Introduction Basic input function Scanf() Syntax Use getche()

Chapter 3 Operators in C Unary operator Binary operator Unary Oerator Increment operator Decrement operator Binary Operator Assignment operator Syntax: Arithmetic operators Addition Operator: Subtraction Operator: Multiplication Operator: Division Operator: Modulus operator Relations operator Logical Operator: Turnary Operator:

Chapter 4 Introductions to Control Statements Introduction If( ) statement Syntax If ( ).. else statement Switch (Var).. Case

Chapter 5 Loops in C Loops in C While Loop Characteristic of while loop Syntax For loop Characteristic of for loop Do.. while loop Characteristic of do.. while loop Nested loop

Chapter 6: - Arrays in C Arrays in C Using variable Using Array Single dimension array Actual declaration Initialization of an array Linear Search Binary Search Sorting of an array Liner Sort Bubble Sort method Double dimension array

Chapter 7 Strings in C Language

Strings in C Language Syntax

Chapter - 8 Functions in C Language Functions in C Language

Chapter 9 Pointers in C

Pointers in C

Chapter 10 Structure and union

Structure And Union

Chapter 11 File handling in C

File Handling In C

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CHAPTER 1

INTRODUCTION TO C PROGRAMMING

Introduction:In our day to day life, we communicate with different types of people. While we interact with them

we use specific language, English, Hindi, Gujarati and so on. A language is generally used to interact andto convey our message to other people. Similarly, to interact with the with the computer system we needsome special language that helps us to interact with it.

Computer language has various categories that are mention below:Lower level language

Binary language (Machine Language)Assembly Language (uses mnemonics)

Higher level languageProlog Prolog Programming logicAlgol Algorithmic LanguageCP/M Control Program for MicroprocessorLISP List ProgrammingBCPL Basic Combine Programming LanguageBASIC Beginners All Purpose Symbolic instruction codeCOBOL Common Business Oriented LanguageFortran Formula TranslatorPascal

Object Oriented LanguageC ++Java

These languages are not powerful enough to process large amount of data or to hold large amount ofdata. So, a language needs that can hold large amount and process it very efficiently. This reason lead todevelop our most popular language C.

Dennis Ritchie, a system programmer, originally develops C language under UNIX operatingsystem in 1970 at Bell Laboratory of USA. When DOS is invented, Dennis Ritchie and Keringon rewritethis compiler for DOS base Operating system in 1972.

Compiler :The problem of computers not understanding our language is solved by using software programs

called translators. This translator is known as compiler.Feature of C:

1. Case sensitive language2. Provide Modular Approach for programming3. Portable Language

Structure of C program :A C program is set of blocks called functions. A function is made up of one or more statements

used for performing a predefined task. A complete C program structure is given below :

DocumentationSymbolic constant definition

File include sectionGlobal variable declaration

main( ){

DeclarationExecutable Statements

}Function 1Function 2Function N


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Documentation Section :This section is an optional section. As the name indicates it is used for the purpose of documen-

tation. It is enclosed within /* and */. Whenever the text is enclosed between /* and */, it is considered as acomment in C. Comments are not processed by C compiler and are left as it is. This section is normallyused to tell about the purpose of program, author, date of creation etc. Comments in C can be added an-ywhere in the program.

Symbolic Constant Definition :There is a symbolic constant like PI. To use such symbolic constant in our program we need to use #de-fine as a prefix to it. Here #define is known as preprocessor directive. It instructs the compiler to replaceall occurrences of symbolic constant with the values specified against it. Normally, symbolic constant aredefined using capital letters.Ex. #define PI 3.14

File include Section :C provides inbuilt or library functions. Some examples are pow(), sqrt(), etc. These functions have a pre-defined purpose. To use them we have to include files that hold information about these functions. Thesefiles are known as header files. The extension of header file is .h. WE use the syntax #include to include header file in our program.

Global variable declaration Section :C variables are governed by scope. A scope of variable is decided by using opening and closing curlybraces { }. This variable can not be used outside the scope. At times we need to use a variable in all thefunctions, such a variable is known as global variable. This variable is defined before defining all the func-tions.

Main Function :All C program contain one function with the name main( ). This is the function from where the execution ofany C program starts. The control is first transferred to this function and from here rest of the operationsare carried out. main() is a user-define function.

User defined function :C provides us a facility of breaking a single program into set of small pieces. These pieces are known asfunctions. In this section we define all the additional functions used in our program. Functions have beendiscussed in detail later on.

Character set in C:Character set refers to the set of character used to provide instruction or command to the com-

puter. In include alphabets, numbers, and special symbols.Uppercase letters Lowercase letters Digits SymbolsA Z, a z 0 9 *, /,,#,(,),{,} etc.

C tokensC tokens are the smallest unit in C language. C tokens are given as follow

1. ConstantsInteger constantsFloating point constantsCharacter constantsString constantsSymbolic constants

2. Keywords3. Identifiers4. Operators5. Special symbols


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1) ConstantsInteger Constant:

1. Integer constant must have at least one digit.2. They must not have a decimal point.3. They can be positive or negative.4. If there is no any sign to integer it is assume to be positive.5. No comma or blank spaces are allowed within the integer constant. e.g. 426, +756,-588 etc.

Real Constant:1. These are generally called as floating point constant. They can be written two forms. That is,

fractional form & exponential form.2. Real constant can be positive or negative.3. They must have decimal point.4. Default sign is positive.5. No comma or blank spaces are allowed in the real number. e.g. 22.45, -85.23, -

11.20, +3.211e-4, 5.6e4 etc.

Character Constants:There are two types of character constants.Single character constant :

1. The character constant is a single alphabet or a single digit or a single special symbol enclosedwithin the single quotation marks.

2. Maximum length of a character is one character. e.g. f, h, =, 8etc.

String constants:String constant refers to the constants values, which remains constants during program execution

enclosed within the double quotes. e.g. India, LCC Infotech Ltd. etc are String constants.

Symbolic constants:We often use certain unique constants in a program. These constants appears in number of plac-

es in the program. One example of such constant is 3.14159 this value represent value of the mathemati-cal constant pi. This types of constant can be defined with the help of #define clause.example:

#define pi 3.14159

2) KeywordsKeywords have special meaning. Keyword is the word whos meaning as already being given to theC compiler. The keywords can not be given as variable name in C. These are also called as reservewords. The C supports 32 different keywords listed below :

Auto Double If Staticbreak else int structcase enum long switchchar extern near typedefconst float register unioncontinue far return unsigneddefault for short voiddo goto signed while

3) IdentifiersIt refers to the name of function, a variable, or an structure. This is the user defined name consist

of a sequence of character or a digits with a letter as a first character, or we can write the definition asfollow

It is a symbolic location in memory in which user can store his data. It may store different types ofvalues according defined in memory.


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Rules to define the identifiers (Rules to define variable name)1. An identifier must starts with an alphabet or underscore.2. It consist alphabets and numbers.3. It should not exceed more than 10 characters but maximum length can be given up to 32 charac-

ters.4. It should not have same name as the reserve word of C.5. No special characters allowed in variable name except under score.

Variable :It is an entity that may vary during the program is executing. Variable

is the name given to the location of the memory. This location can contain integer, real or characterconstants.

Variable DeclarationAfter defining a variable we must defined to the compiler. Declaration does two things:1. it tells the compiler what the variable name.2. it specifies what type of data the variable can hold.

Declaration of variable must be done before they are used in program. We can declare variableas followsSyntax:

DataType variableName;Example:

int age;char ch;char name[10];float rate;

Here type means type of value stores in variable and name means name of an identifier.

Initialization of variable (Assigning value to variable)We can initialization variable as follow

Syntax:variableName = value;

Example:age = 25;

4) Operators :Operators are the special symbol use to perform special operation (for example, arithmetic &

logical) on operands. Operands are the variables, constants or expressions on which operators per-form operation.

As per the number of operands required by the operator, it is classified in three categories:1. Unary operators2. Binary operators3. Ternary operators

These operators require one, two and three operands respectively for performing their operation. Op-erators will be discuss in detail later on.

Basic Input / output functionsC has various types of basic input and output function. They are used to accept input from stan-

dard input device, or to print output on standard output device.

Standard output function:Standard output function printf( ) is used to print output to standard output device, monitor. It is a

library function defined in stdio.h (standard input output header file)printf

This formatted output function statement defined in stdio.h file used to print the string or the val-


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ues of variables on the output screen.

Syntax:printf(, );

Here, the format string will contain the string and the format specifiersor format codes to display the values of variables in the sequence of format specifiers.e.g.

printf(Welcome to C);

it will print following string on the output screen.

Welcome to C

Sample C program 1.1:#include void main(){

printf(Welcome to C program);}Write above program in TurboC editor and save with .c extension. It needs to translate into machinereadable format. To do this we have to compile this program.What is compilation?

Compilation is the process of translating program written in any higher-level language to itsequivalent machine codes.How to compile?

To compile a program press ALT + F9; compile will translate your program into object code.How to run a program?

To run a program press CTRL + F9 from keyboard. Your program will run and you will get youroutput.How to see output of a program?

To see output of a program press ALT + F5 key from keyboard.

Escape Sequences

Character Meaning\n New line\t Tab\b Backspace\v Vertical tab\a Audible Alert (Bell)\r Carriage return\f Farm Feed\\ Backslash\ Single Quote\ Double Quote

Separators

These are the symbols which are used to indicate where groups of codes are dividedand arranged. They are basically used to define the shape and function of the program code. Themost commonly used separator is semicolon. All these separators are listed below:


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Separator Name Purpose

( ) Parenthesis

Used to contain lists of parameters in function definition and call.Also used for defining precedence in expressions, containing ex-pressions in control statements, and surrounding cast types.

{ }Curly

Braces

Used to contain the values of automatically initialized arrays. Alsoused to define a block of code for classes, functions, and localscopes.

[ ]Square

bracketsUsed to declare array types. Also used when dereferencing arrayvalues.

< >Angle

BracketsUsed to include header files in the program.

; Semicolon Terminating the statement/line

, CommaSeparates consecutive variable declarations. Also used to chainstatements together inside a for loop statement.

Doublequotes

Used to declare any string or group of more than one characters

Singlequotes

Used to declare a single character constant

Sample program :#include #includevoid main(){

clrscr();printf(Programming in C is easy.\n);printf(\tAnd so is Pascal.);getch();

}The output of above program is :Programming in C is easy.

And so is Pascal.

Exercise for printf function:1. Write a program to print different five statement of your favorite picnic place.2. Write a program to print at least five statement for cricket game3. Write a program to print your bio-data on screen4. Write a program to print at least five statement about you and your likes and dislikes5. Write a program to display five statements about legendary personality of your choice.

DATA TYPESType of value that can be assigned to an identifier is known as data types. C language uses set ofkeywords to relate a data with its value. These keywords identify two things, the type of value that canbe stored in an identifier and the memory space required by an identifier. Each data type is allocated afixed memory space in C. It is denoted by bytes.

1 byte = 8 bitsThe three basic data types are integer, float and character.


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INTEGERThese are whole numbers, both positive and negative. Unsigned integers (positive values on-ly)are supported. In addition, there are short and long integers. The keyword used to define in-tegers is,

intAn example of an integer value is 32. An example of declaring an integer variable called sum is,

int sumsum = 20

DATA TYPE DESCRIPTION RANGE BYTE RE-QUIRED

EXAMPLE

intshort int

To store a positiveor negative wholenumber.

-32768 to+32767

2 int amount;short int a;

long int -2147483648 to+2147483647

4 long int bal;

unsigned int To store a positivewhole number

0 to65535

2 unsigned int mark;

unsigned long int 0 to4294967295

4 unsigned long int ctr;

FLOATThese are numbers which contain fractional parts, both positive and negative. The keywordused to define float variables is,

floatAn example of a float value is 34.12. An example of declaring a float variable called money is,

float moneymoney = 0.12


EXAMPLE

float To store a positiveor negative realnumber.

+/- 3.4e-38 to +/-3.4e +38

4 float amount;

double +/-1.7e-308 to +/-1.7e +308

8 double total;

long double 10 long double credit;

CHARACTERThese are single characters. The keyword used to define character variables is,

charAn example of a character value is the letter A. An example of declaring a character variable calledletter is,

char letterletter = 'A'

Note the assignment of the character A to the variable letter is done by enclosing the value in singlequotes. Remember the golden rule: Single character Use single quotes.


EXAMPLE

char To store a charac-ter.

-128 to +127 1 char gender;

unsigned char 0 to 255 1 unsigned char choice;

In order to print the values of the variables printf can also be used as:


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int y = 14, s = 10;printf(Values are : %d and %d,s, y);

this will print the following statement on the screen:

Values are: 10 and 14Here the %d is called as integer format specifier and used to print the integer value of vari-able on the screen. Such 16 different format specifiers / format codes are used in printfas well as scanf. These are listed below:

Format Specifiers / format codes%c Character format specifier.%d Decimal integer format specifier.%e Scientific notation for floating point format specifier.%E Scientific notation for floating point format specifier.%f Floating-point format specifier.%i Integer format specifier (same as %d).%s String format specifier.%u Unsigned integer format specifier.%ld Double format specifier.

Sample C program with format modifiers 1.2#include #include void main(){

clrscr();printf(I have %d rupees in my pocket., 100);

}

Sample C program 1.3#include#includevoid main(){int a;float b=10.444;char choice ='x';clrscr();a = 10;printf("The value of a is %d",a);printf("\nThe value of b is %f",b);printf("\n answer = %c",choice);getch();}

Sample C Program 1.4#include #include void main(){


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int age;clrscr();

age=25;printf(Age is initialize by %d, age);

}

Standard input functionscanf

This formatted input function statement defined in stdio.h file and used to accept the values of va-riables from the keyboard.

Syntax:scanf(, );

Here, the format string will contain the format specifiers or format codesto accept the values of variables in the sequence of format specifiers. For example:

int var1;float var2;scanf(%d%f, &var1, &var2);

This statement will read an integer number and a float number from keyboard and storethese values in var1 and var2 respectively. The scanf allows all the above format specifiers to usefor inputting the values.

Sample C program 1.5#include#includevoid main(){int a,b,ans;clrscr();printf("Enter two numbers:");scanf("%d",&a);scanf("%d",&b);ans = a * b;printf("%d * %d = %d",a,b,ans);getch();}

Output :Enter two numbers: 102010 * 20 = 200

A Sample program 1.6// to calculate area of circle.#include #include #define pi 3.14159void main(){

float r=2.5, a=0;clrscr();printf(\n\t Area of a Circle is );a=pi*r*r ;


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printf(%d,a);getch();

}

Summary of major points:1 program execution begins at main()2 keywords are written in lowercase3 statements are terminated with a semicolon4 text strings are enclosed in double quotes5 C is case sensitive, use lowercase and try not to capitalize variable names6 \n means position the cursor on the beginning of the next line7 printf() can be used to display text to the screen8 The curly braces {} define the beginning and end of a program block.


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CHAPTER 2

FORMATTED INPUT OUTPUT FUNCTIONS

Computer basically has three parts namely, input, process and output. Similarly, any program can bethought of as having three parts, input, process and output. Input means to read data from some inputdevices. Output means to write processed data to the output device. I/O in C is done through some stan-dard library functions.Input functions : getchar( ), getch( ), getche( ), getc( ), gets( ), scanf( )Output functions : putchar( ), putc( ), puts( ), printf( )

getchar( ):To read a single character from user / keyboard, a function called getchar( ) is used. It does not

assign value to variable till we press an enter key from keyboard. It echo the character on screen.Syntax:

Variable_name = getchar( );Example:

char choice;choice = getchar( );


char ch;clrscr();printf(Enter any character );ch = getchar();printf(\n\t Entered character is %c, ch);

}

getche( ):getche( ) function is also used to input a single character. It assign character to a variable, without

pressing enter key from keyboard. It also echo character on screen. The getche( ) function is similar togetchar( ) except that the function getche( ) is included in the conio.h header file.syntax:

Variable_name = getche( );Example:

char choice;choice = getche( );


char ch;clrscr();printf(Enter any character );ch = getche();printf(\n\t Entered character is %c, ch);

}getch( ) :

It is also a function which accepts a single character. it assigns value to variable as we type inform keyboard. It accepts a character form user but does not echo it on screen means character will notbe visible to the screen.


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syntax:Variable_name = getch( );

Example:char choice;choice = getch( );

Sample C Program 2.3A program to accept a character and print it.#include #include void main(){

char ch;clrscr();printf(Enter any character );ch = getch();printf(\n\t Entered character is %c, ch);

}

gets( ):We call a group of character as a string. A string in C is enclosed within double quotation. It al-

ways ends with a null character (\0). We can use a sequence of getchar( ) functions to accept a string.Alternatively we use gets( ) function to read string. It is a library function, stored in stdio.h header file.syntax:

gets( Variable_name );Example:

char name[50];gets( name );

Sample C program 2.4#include #include void main(){

char name[10];clrscr();printf(Enter your Name please );gets(name);printf(\n\t Name entered is %s, name);getch();

}

Sample program 2.5// A program to accept name, address, city form user and print it.#include #include void main(){

char name[10], addr[15], city]15];clrscr();printf(Enter Name: );gets(name);flushall();printf(Enter Address: );gets(addr);flushall();printf (Enter City: );gets(city);


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flushall();

printf(\n\t Name %s: , name);printf(\n\t Address %s: , addr);printf(\n\t: city %s ,city);getch();

}

getc( ) and putc( ) functions are discussed in detail later on.

putchar( ) :putchar( ) function prints a single character on a screen. It take a variable of type character as an

argument an displayed content of it.syntax:

putchar( variable_name );example:

char ch=A;putchar(ch);


char ch=x;clrscr();printf(Character is );putchar(ch);putchar(\n);putchar(y);getch();

}Output :Character is xy

puts( ) statement:puts( ) statement is used to display string type data. It take a string variable as an argument, or it

also take a constant string as argument.Syntax:

puts(variable_name);Example:

puts(India);

Sample C program 2.7#include #include void main(){ clrscr();

puts(Welcome to C program);}


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char name[10]=Ashok;clrscr();puts(Name entered is );puts(name);getch();

}

Exercise:1. Write a program to accept your name, address, city and phone and print it.2. Write a program to accept sales man name and his age and print it on screen.3. Write a program to accept employee name, his department, and his basic salary and print it.4. Write a program to accept student name, roll no, and marks of five different subjects and print it.5. Write a program to accept item name, quantity and rate and print it on screen.


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CHAPTER 3

OPERATORS IN C

Operators are the special symbol use to perform special operation (for example, arithmetic& logical) on operands. Operands are the variables, constants or expressions on which operatorsperform operation.An operator is the special capable of performing any type of arithmetic operation.They are used in program to manipulate data and variable. They usually form a part of mathematical oflogical expression. C has rich set of operators.

The operators in C can be categorized into eight types :1. Arithmetic operator2. Assignment operator3. Relational operator4. Increment and decrement operator5. conditional operator6. logical operator7. bitwise operator8. special operator

1 ) Arithmetic operatorsArithmetic operators used to perform any type of arithmetic operation such as addition, subtrac-

tion, multiplication and division etc. Arithmetic operator has further following type:1. Addition operator ( + )2. Subtraction operator ( )3. Multiplication operator ( * )4. Division Operator ( / )5. Modulus Operator ( % )

Addition Operator:This operator is used to perform addition on any numerical operand.e.g. c = a + b, c = c + 1 etc.

Subtraction Operator:This operator is used to perform subtraction on any numerical operand.e.g. c= a b, c = c 1

Multiplication Operator:This operator is used to perform multiplication on any numerical operand.e.g. c = a * b, c = c * 2

Division Operator:This operator is used to perform division on any numerical operand.e.g. c = a / b, c = c / 3

Modulus Operator:This operator is used to perform modulus operation on any numerical operand. e.g. c = a % 10, c

= a %10.

2) Assignment operatorAn assignment operator is used to assign value to variable. Assignment always performed right to

left.Syntax:

Variable = valueExample:

Age = 25;

3) Relational Operators:Relational operators are used to perform to or more values to set relation between them whether

one operand is greater, equal, less or not.Relational operand has further more type:

1. Greater then operator ( > )2. Less then operator ( < )3. Greater then or equal to operator ( >=)


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4. Less then or equal to operator ( b ? a : bhere if the condition a>b will be true then the value of max will be a otherwise the value of max will beb.

6) Logical Operators:Logical operators are used to test more then one condition at time. Logical operators are:1. And Operator &&2. OR Operator ||3. Not Operator !

Logical AND is used when all the given condition must be satisfied. Logical OR is used when any one ofthe given condition must be satisfied.

7) Bitwise Operators:Internally the data is stored in bits. C allows us to operate directly at bit level using bitwise operators. Thebitwise operators available in C are :

1. Bitwise And &2. Bitwise OR |3. Bitwise Not ~4. Bitwise Ex-OR ^5. Left shift by number of bits specified >


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8) Special Operators:C provides special operators like sizeof( ), ,, ., &, *. The sizeof( ) operator is a special operator usedto return size of bytes required to store an entity. For example val = sizeof(int) will give value 2 to val.This is because data type int uses 2 bytes in memory space.

Sample Program 3.1: addition of two integer numbers.#include #include void main(){

int N1, N2, sum;clrscr();printf(Input value to N1: );scanf(%d,&N1);printf(Input value to N2: );scanf(%d,&N2);sum = N1 + N2;printf(\n\tSum of %d + %d = %d, N1,N2,sum);getch();

}

Similarly, we can perform subtraction, multiplication etc.

Sample Program 3.2 multiplication of two numbers.#include #include void main(){

float a, b, ans;clrscr();printf(Enter two numbers : );scanf(%f%f,&a,&b);ans = a * b;printf(\n\t Multiplication of %f * %f = %f, a,b,ans);getch();

}

Sample Program 3.3 : Division of two numbers#include #include void main(){

int N1, N2, N3;clrscr();printf(Input value to N1: );scanf(%d,&N1);printf(Input value to N2: );scanf(%d,&N2);N3 = N1 / N2;printf(\n\t Division of %d / %d = %d, N1,N2,N3);getch();

}Output :Input value to N1 : 7Input value to N2 : 3Division of 10/3 = 2


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Here, the variable n1 and n2 are type of integer so value of n3 will bi 2 in integer not 2.33333. Itcan not be in float.

A Sample program 3.4// A program to accept number and find its square.#include #include #includevoid main(){

double n, p;clrscr();printff(Enter any number for which you want to find square: );scanf(%lf,&n);p=pow(n,2);printf(\n\t Square of %lf is %lf, n, p);getch();

}

A Sample program 3.5// A program to accept number and find its square root.#include #include #includevoid main(){

float n, s;clrscr();printff(Enter any number for which you want to find square root: );scanf(%f,&n);s=sqrt(n);printf(\n\t Square root of %f is %f, n, s);getch();

}

A sample program 3.6// A program to enter currency in Indian rupees and convert it into dollars, and pound.#include #include void main(){

float rs, pnd,dlr;clrscr();printf(Enter Indian Rupees: );scanf(%f,&rs);dlr=rs/48.5;printf(\n\t Rupees %f equals dollars %f, rs, dlr);pnd=rs/79;printf(\n\t Rupees %f equals pound %f, rs, pnd);getch();

}A sample program 3.7// A program to enter Distance in km and convert it into meter, feet and inches#include #include void main(){

float d, m, f, i;


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clrscr();printf(Enter Distance in KM: );scanf(%f, &d);m=d*1000;printf(\n\t Distance in Meter is %f , m);f=m*3.33;printf(\n\t Distance in feet is %f, f);i=f*12;printf(\n\t Distance in inches is %f, i);getch();

}

A sample program: 3.8// A program to convert temperature entered in Celsius to its equivalent Fahrenheit degree.#include #include void main(){

float c, f;clrscr();printf(Enter temperature in Celsius: );scanf(%d, &c);f=9.0/5.0 * c + 32.0;printf(\n\t Temperature in Fahrenheit is %f, f);getch();

}A sample program 3.9// A program to convert temperature entered in Fahrenheit degree and convert to its equivalentCelsius degree.#include #include void main(){

float c=0, f=0;clrscr();printf(Enter temperature in Fahrenheit: );scanf(%d, &f);c=(5.0/9.0) * (f 32);printf(\n\t Temperature in Celsius is %f, c);getch();

}

A Sample program 3.10// Program to find area of a circle and circumference of a circle.#include #include #define PI 3.14void main(){

float r, a, c;clrscr();printf(Enter Radius of a Circle : );scanf(%d, &r);a=PI * r * r ;c= 2 * PI * r ;printf(\n\t Area of a circle is %f, a);printf(\n\t Circumference of a circle is %f, c);getch();


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}

A Sample program 3.11// A program to enter salary and sale amount of a salesman and calculate his commission @ 12%of sales amount and display total salary;#include #include void main(){

float sal,amt,com,total;clrscr();printf(Enter Salary of a Salesman: );scnaf(%d, &sal);printf(Enter sales amount of a Salesman: );scnaf(%d, &amt);com = amt * 0.12 ;total = sal + com;printf(\n\t Salary of a salesman: %f,sal);printf(\n\t Commission %f, com);printf(\n\t Total salary: %f, total);getch();

}

A Sample program 3.12//Example of increment - decrement operator.#include#includevoid main(){

int a=10,b=20,c;c = a++;printf("a = %d b = %d c = %d",a,b,c);- - b;printf("\nb = %d",b);c = ++a + b--;printf("\n a = %d b = %d c = %d",a,b,c);getch();

}Output :

a = 11 b = 20 c = 10b = 19a = 12 b = 18 c = 31

A Sample program 3.13//Example of conditional opertor.#include#includevoid main(){int a=70,b=50,max;clrscr();max = (a>b) ? a : b;printf("Maximum number is %d",max);getch();}


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A Sample program 3.14//Example of sizeof operator.#include#includevoid main(){int a=10,b;float c;clrscr();b = sizeof(a);printf("The value of a is %d",a);printf("\nSize of a is %d",b);printf("\n Size of float variable is %d",sizeof(c));getch();}

A Sample program 3.15// program to find ascii value of a character#include#includevoid main(){char ch;clrscr();ch = 'A';printf("character is %c",ch);printf("\nAscii value is %d",ch);getch();}/* ASCII = American standard code for information interchange.

ASCII for A = 65 a = 97*/

Exercise:1. Accept marks of five different subjects from the user calculate total and average and display it.2. Accept a character and convert it to uppercase character and vise-versa.3. Accept principle amount, rate of interest and number of years from user and find simple interest.4. Accept simple interest, rate of interest and number of year from the user and find principle

amount.


22

CHAPTER 4

INTRODUCTIONS TO CONTROL STATEMENTS

Introduction:So far we learn about data types, basic input and output function etc. now we will learn about

branching control to some other process. Before we learn about it. We will look at some programmingconstruct, i.e. sequential programming, selective programming, and iterative programming. Sequentialprogramming is that in which program starts from top and ends with last line without branching control toother process, and Selective programming is that in which control can be branch to some other processThis is done using control statements in C Language. A flow control statement is used to control flow ofprogram execution depending upon given condition. C language has two types of control statements.

1. if statement* Simple if statement* if else statement* nested if* else if ladder

2.. switch statementSimple if Statement:

if statement is a powerful decision making statement and is used to test one or more than onevalue of condition at a time. It is also used to control the flow of execution of statements. It is basically atwo way decision statement and is used in conjunction with an expression. It is used when we have morethan one option to select the process and depending on condition we want to read or execute theprocess.Syntax:

if(condition){

action;}Statement x;

Here condition is given criteria or test condition that should be a logical expression, and action meansstatements of process to be performed when given criteria satisfied. The statement block may be a singlestatement, or a group of statement. If the test condition is true, the statement block will be executed; oth-erwise statement block will be skipped and execution will be jump to the statement-x. Remember, whencondition is true both statement block and statement-x are executed in sequence.

Sample Program 4.1// Write a program to check whether entered value is more than 100 or not.#include #include void main(){

int n;clrscr()printf(Enter any number : );scanf(%d,&n);if(n > 100){

printf(\n\t Value %d is more than 100,n);}

}

in above example if given value is less then 100 then it wouldnt display any thing on the screen, becausewe could not specified alternate option for the if statement.

if .. else Statement:To perform an operation in both the case means if given condition is true or given condition is false, thefirst test determines whether condition is true or not. if condition is not true then it executes statement


23

block immediately after if statement otherwise it executes statement block immediately after else state-ment. we could write the previous program as follows using if .. else statementSyntax:

if(condition){

action;}else{

action;}

in above example if given value is less then 100 then it displays message on the screen, because wespecified alternate option for the if statement means if given condition is true then it executes statementsafter the if statement, if given condition is false then also it execute the statements after else statement.Note:

1. Statements inside the ifs curly braces are called as if block and statements for elses curlybraces are called as else block.

2. There is no necessity to have an else for if but, each else must match an if statement elsethere will be a compiler error. The error will beMisplaced else.

3. If there is only one statement inside if as well as else block, we can eliminate the curly braces.

Sample Program 4.2/* program to display greater number between two numbers */#include#includevoid main(){int a,b;clrscr();printf("Enter two numbers :");scanf("%d%d",&a,&b);if(a>b)

printf("greater no is a %d", a);else

printf("greater no is b %d", b);

getch();}

Sample Program 4.3/* program to check whether entered number is even or odd */#include#includevoid main(){int a;clrscr();printf("Enter a integer number \t :");scanf("%d",&a);if(a%2 == 0)

printf("%d is Even number.",a);else

printf("%d is Odd number.",a);getch();

}


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Nested if elseIf we write an entire if - else construct within the body of the if statement or the body of

an else statement. This is called nesting of if- else.Syntax:if(condition){

//statements1if (condition){

// statements2}else{

// statements3}

}else

// statement 4Here, the inner condition executed only when the outer condition of if is true. This hierarchy of nestingof if can be extended in deep with any number of if-else statements.

Sample Program 4.4/* program to find maximum number between three numbers */#include#includevoid main(){

int a,b,c,max;clrscr();printf("Enter 3 numbers \t");scanf("%d%d%d",&a,&b,&c);if ( a > b ){

if ( a > c )max=a;

elsemax = c;

}else{

if ( b > c)max=b;

elsemax=c;

}printf("Max = %d ",max);getch();

}

if .. else if statement (else if ladder) :There is another way of putting ifs together when multipath decision are involved. A multipath

decision is a chain of ifs in which associated with each else is an if. It makes following general form of if ..else if structure:


25

Syntax:if(condition){

action;}else if(condition){

action;}else{

action;}

It required when we have more then one conditional statements. It is applied when we want to applygrades to students or to decide who is eligible for bonus in company etc.

A Sample program 4.5//program to display grade of the student based on marks obtained.#include#includevoid main(){float marks;clrscr();printf("Enter marks :");scanf("%f",&marks);if(marks>80){printf("Grade is A.");}else if(marks>70){printf("Grade is B.");}else if(marks>50){printf("Grade is C.");}else if(marks>35){printf("Grade is D.");}else{printf("Student is Fail.");}getch();}

Example:1. Write a program to enter sales amount of a salesman and salary of a salesman and calculate is

commissionRates of commission are:Sales amount > 15000 rate of commission is 15%Sales amount between 8000 and 15000 rate of commission is 12%Sales amount between 5000 and 8000 rate of commission is 10%Sales amount less then 5000 rate of commission is 8%


26

2.3. Write a program to check given year is leap year or not.4. Write a program to check entered number is positive, negative or zero.5. Write a program to check whether the person is eligible for voting or not.

Switch case statement :C language has a built-in multiway decision statement known as switch statement. It is another

type of control statement used to test limited scope of condition like to check constant expression like vo-wel or operator etc. we can not check large range of data in switch statement. It tests the value of variable(or expression) against a list of case values and when a match is found, a block of statements associatedwith that case is executed. The general form of switch statement is shown below:

The expression is an integer expression or characters,. value-1, value-2 .. are constants orconstant expression ( evaluable to an integer constants, and are known as case labels. Each of thesevalues should be unique within a switch statement, block-1, block-2 . Are statement blocks. Note thatcase labels are ends with colon (:)

Syntax:switch(variable or expression){

case constexpr1:action1;break;

case constexpr2:action2;break;

case constexprN:actionN;break;

default:action;

}Sample Program 4.5//display word according to given number.#include#includevoid main(){int choice;clrscr();printf("Enter any number between 1 to 5 :");scanf("%d",&choice);switch(choice){case 1:

printf("One");break;

case 2:printf("Two");break;

case 3:printf("Three");break;

case 4:printf("Four");break;

case 5:printf("Five");

default :


27

printf("Invalid choice.");}getch();}

A Sample program 4.6// calculator#include#includevoid main(){int a,b,ans,choice;clrscr();printf("Enter two numbers :");scanf("%d%d",&a,&b);printf("\n Calculator");printf("\n1. Addition");printf("\n2. Subtraction");printf("\n3. Multiply");printf("\n4. Division");printf("\n\n Enter your choice 1 2 3 4 \t");scanf("%d",&choice);

switch(choice){case 1:

ans = a + b;printf("Addition = %d",ans);break;

case 2:ans = a - b;printf("Subtraction = %d",ans);break;

case 3:ans = a * b;printf("Multiplication = %d",ans);break;

case 4:ans = a / b;printf("Division = %d",ans);break;

default :printf("Invalid choice.");

}getch();

}


28

CHAPTER 5

LOOPS IN C

Many times it is necessary to execute several statements repetitively for certain number oftimes. In such cases, we can use looping statements of C programming language. The statements areexecuted until a condition given is satisfied. Depending upon the position of the condition in the loop,the loop control structures are classified as the entry-controlled loop and exit-controlled loop. They arealso called as pre-test and post-test loops respectively.

If I ask you to print your name 5 times what you do? Naturally, you will write five printf statementsright?. Because you dont know about the loop process. A loop is a process of executing statements with-in the loop till given condition is true. It reduce redundancy of code of program. C language has basicallythree types of loops

1. while loop2. do .. while loop3. for loop

while loopThe simplest of all the lopping structure in c is the while statement. A while loop is generally

known as entry-conditional loop, then the body of the loop is executed. It is also known as pre tested loopbecause it test the condition before it enters in loop and executes statements within the body of the loops.Characteristic of while loop

1. Pre tested loop2. It executes statement within the body of the loop till given condition is true.3. If condition in the beginning is false entire loop skips and statement executes immediately

after the body of the loop.Syntax:

while(condition){

statements;}Here, the condition is evaluated first, if it is true then loop statements or body of the loop is ex-

ecuted. After this the program control will transfer to condition again to check whether it is true or false. Iftrue, again loop body is executed. This process will be continued until the condition becomes false.When is becomes false, the statements after the loop are executed.

Sample Program 5.1:#include #include void main(){

int count=1;clrscr();while(count


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Sample program 5.2:// to print odd numbers between 1 to 20 in descending order.#include#includevoid main(){int a=20;clrscr();while(a>0){printf("%d\n",a);a = a - 2;}getch();}

Sample Program 5.3:A program to find average of n numbers.#include #include void main(){

int n, c=1;float s=0, a, no;clrscr();printf(Enter Limit to N:);scanf(%d, &n);while( c


30

Syntax:do{

statements;} while(condition);

Characteristic of do .. while loop1. It is post tested loop2. It executes the statements within the body of loop till given condition is false3. if condition in the beginning is false it executes statements within the body of loop at least

once.

Sample Program 5.4#include #include void main(){

int count;clrscr();do{

printf(\n\tcount = %d,count);count++;

} while(count


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Sample Program 5.6A program to print multiplication table of given number.// to print multiplication table.#include#includevoid main(){int a,n;clrscr();printf("\n\tEnter number :");scanf("%d",&n);a = 1;do{printf("\n\t%d * %d = %d",n,a,a*n);a++;}while(a =1);getch();}

No. while loop do-while loop1 It checks the condition at the start of the loop It checks the condition at the end of the loop2 This is of type entry controlled loop structure. This is of type exit controlled loop structure.

3 The while loop is called as pre- test loop. The do-while loop is called as post-test loop.

4 It is not guaranteed that how many times the loopbody will get executed.

The loop body will be executed at least once.

5 Syntax:while(condition){

//loop body}

Syntax:do{

//loop body}while(condition);


32

Exercise:1. Generate the following Fibonacci series using while loop till n number. Accept n from user. 0 1

1 2 3 5 8 13 n2. Write a program to find sum of all even numbers from n to m. Accept values of variables n and m fromkeyboard.3. Write a program to print numbers between 1 to n and its square.4. Write a program to input a number and display its all digit in reverse order.

For LoopThe for loop is another entry-controlled loop that provides more concise loop control structure. It

is also an example of pre tested loop. We can use this loop only when we know the number of iteration.Loop contains initialization, test condition, and increment together.Syntax:

for(initialization; condition; increment/decrement){

statements;}

The execution of for loop statement takes as follows:1. Initialization of loop control variables is done first using assignment operators such as:

i = 1 or count = 0 etc. Remember this part is executed only once.2. The condition given afterwards is checked then. If this condition is true, the statements inside theloop are executed. Else program control will get transferred nest statement after the loop. The condi-tion can be combination of relational as well as logical operators such as:

count < 103. When the body of the loop is executed, program control will get transferred back to forstatement for executing the third statement that is, increment/decrement. In this part the loop con-trol variables value is incremented or decremented. Then program controls the condition again tocheck whether it is true or not. If true, the loop body executed again. And the process is continuedagain until the condition evaluates to false.

Characteristic of for loop1 Pre tested loop2 It executes statement within the body of the loop till given condition is true.3 If condition in the beginning is false entire loop skips and statement executes immediately

after the body of the loop.

Sample Program 5.8#include #include void main(){

int count;clrscr();for(count=1; count


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A Sample program 5.9Program to print series of numbers and its cube.#include#includevoid main(){int i,n;clrscr();printf("Enter ending value :");scanf("%d",&n);printf("\nNumber Square\n");for(i=1;i


34

}printf("\n");

}getch();

}

A sample program 5.12A program to print x^y and 1/x^y using for loop#include #include void main(){

long pass=0;int n=0;double q=0;clrscr()printf(-----------------------------------------------------------);printf( 2 to power n n 2 to power n);printf(-----------------------------------------------------------);p = 1;for(n=0; n


35

}}

similarly, you can nest for loop and do while loop.

Sample Program 5.13Create following pattern on screen** ** * ** * * *#include #include void main(){

int i=1,j;clrscr();while(i


36

scanf(%lf, &number);if(number == 9999)

break;if(number < 0){

printf(\n\t Number is negative);negative++;continue;

}sqroot = sqrt(number);printf(\n\t Number = %lf, sqroot);count ++

}printf(\n\t Number of items done = %d\n, count);printf(\n\t Negative intes = %d\n, negative);getch();

}Sample Program 5.15A program to print following pattern on screen12 23 3 34 4 4 45 5 5 5 5

#include #include void main(){

int i,J;clrscr();for(i=1; i


37

The output of this program will be:1011

Because, when value of x becomes 12, the condition will be evaluated to true and break get executed.

The continue statementThe continue statement is used to continue the next iteration of the loop by skipping the statements inbetween. That is, when the continue is executed the statements following is will not be executed,the program control will directly transfer to next iteration of the loop by increment or decrement. Gen-erally, the continue is associated with if-statement. General form of using continue is :

continue;Example

int x;for(x = 10;x < 20; x++){

if(x%4==0)continue;

printf(%d\n);}

The output of this program will be:1011131415171819It has skipped the numbers which are divisible by 4, for which we have used the continue state-

ment.


38

CHAPTER 6 :-

ARRAYS IN C

An array is a collection of group of variable or data items that can share common name to accessit. All elements in an array are stored consecutively. An array can be of any variable type. A specific valuestored in an array can be displayed by a number called index or subscript.The ability to use a single name to represent a collection of item and to refer to an item by specifying theitem number enables us to develop concise and efficient program. Suppose you want to store marks offive students that we can store in different variables but in array we have only one variable and we canstore marks of five students in an array as givenUsing variableint m1=36,m2=36, m3=36,m4=36,m5=36;Using arrayint marks[5]={36,45,54.68,75};Arrays are very helpful in C programming. You can manipulate number of variables at a time. We canstore more than on value in a using array. Arrays have two category given below:

1) Single dimension2) Two dimension

Single dimension array:A list of items can be given one variable name using only one subscript and such a variable is

called a single-subscripted variable or a single dimension array. In mathematics, we often deal with va-riables that are single-subscripted. The subscript can begin with number 0. Like any other variable arraysmust be declared before they are used. The general form of the array declaration is given below:Syntax:

DataType ArrayName[size]

Here type means data type of a array style variable, name is the name of array, and boundary meansnumber of elements within the array.

Example: Declaration of Array:int marks[5];

Initialization of an array:Like other variable we can initialize an array. It prevent garbage value in processing. We can in-

itialize an array as follows:Syntax:

variable[index]= value;Example:

marks[0] = 50;marks[1] = 25;. And so on.

orint marks[5]={ 50,25,23,56,70}; // declaration with initialization

Sample Program 6.1:Program to Input five value to an array and print it on screen#include #include void main(){

int a[5], i;clrscr();printf(Enter Five values : );for(i=0; i


39

printf(\n\t%d,a[i]);getch();

}similarly you can manipulate array using arithmetical operators and calculate sum of arrays. Exampleshows summation of a array.Sample Program 6.2:Program to Input five value to an array and calculate of sum and print it on screen#include #include void main(){

int a[5], i, sum=0;clrscr();printf(Enter Five values : );for(i=0; i


40

scanf("%s",&name);printf("name = %s",name);for(i=0;i


41

clrscr();

printf(Enter values to array\n);for(i=0; i sv)high=mid -1;

else if(n[mid]==sv){

f=1;break;

}}

if(f == 1)printf(\n\t Search value found in array);

elseprintf(\n\t Search value found in array);

getch();}above program search value within the array using binary search.

Sorting of an arraySorting is a process in which we arrange an array either in ascending order or in descending or-

der, C Language generally provides two types of searching methodsLinear sorting or sequential sort methodBubble sort method.Linear sort

In l Liner sort we assume that the first element of the array is the highest value we compares itwith the next element of array if the first element value is larger then the second, exchange it, and repeatprevious steps by comparing value to next element till all elements in array are sorted.Sample Program 6.7Program to sort an array using liner sort#include #include void main(){

int n[5], i, j, t=0;clrscr();

printf(Enter Values to an array:\n);for(i=0; i


42

for(i=0; i


43

[0][0] [0][1] [0][2] [0][3]

[1][0] [1][1] [1][2] [1][3]

[2][0] [2][1] [2][2] [2][3]

[3][0] [3][1] [3][2] [3][3]

[4][0] [4][1] [4][2] [4][3]

Bubble sort methodIn bubble sort method the smallest value comes up like a bubble. In this method we starts with

the last element assuming that value of the last elements is the smallest one then it compare with theprevious element if ii really small then previous element exchange them, and repeat all step till entire ar-ray is sorted.Sample Program 6.9//Program to sort an array using bubble sort#include #include void main(){

int n[5], i, j, t=0;clrscr();printf(Enter Values to an array:\n);for(i=0; i


44

there respective row and column number as,table[2][3] = 10;

table[1][1] = -52;A two dimension array contains number of rows and number of columns, to read or to write a two dimen-sion we need nested loop. Possible operation can be performed on double dimension is, reading and writ-ing an array, transpose of matrix, addition of matrix and multiplication of a matrix.Two dimensional arrays can also be initialized as.

int table[2][2] = {8, 5, 9, 6};It will initialize the array as shown below,

8 5

9 6Following declaration and initialization is more understandable than previous one.

int table[][] = {{8, 5}, {9, 6}};orint table[][] = {

{8, 5},{9, 6}

};

Sample Program 6.10// Program to read and print values of two dimension array.#include #include void main(){

int n[3][3], i, j;clrscr();printf(Enter 9 numbers : \n);for(i=0;i


45

CHAPTER 7

STRINGS IN C LANGUAGE

The string is sequence of characters that is treated as a single data item. In general, thecharacter array is called as string. Any group of characters defined between double quotationmarks is a string constant. Such as

The C Programming Language.Declaring a string

C does not support string as the data type. However is allows us to represent strings ascharacter arrays. It can be declared as

char string_name[size];Here, string_name is the valid variable name given to the string and

size determines the number of characters in the string. For example:

char city[10];char name[30];

Here, city is the character array or a string can be stored with 10characters. The name will store 30 characters as well.Initializing a string

Like numerical arrays the strings can also be initialized when they are declared which is re-ferred as compile time initialization. It can be done in following three forms:

char city[6] = Nashik;char city[ ] = Nashik;char city[6] = {N, a, s, h, i', k };

For initializing the string at run-time, we use scanf function with %s format specifier such as:char str[10];scanf(%s, str);

This statement will initialize the string str by taking the input from the keyboard. This will read the cha-racter sequence until occurrence of first separator such as space character, tab or enter and store it intostr. We can also use the following function to input the string including spaces.

char str[10];gets(str);

The gets() function defined in stdio.h file reads the string from the keyboard until the en-ter is not pressed.For printing the string, we can use the printf function in the similar format such as:

printf(%s, str);Note:A string consists of characters which is known as string. String terminates by a terminator charactermeans a NULL character that is \0. When we input a string from key board and when we stopped input-ting string C compiler automatically adds a special at the end of string which is known as NULL ( \0 )character.

There are various types of functions which can be helpful to manipulate string, to use string function wemust include string.h header file, string functions are given below:

1. strlen( ): it is used to find the length of a string;eg. Len = strlen(India);

This will give the length of a given string India. It will stor 5 as length of a sting in variable Len.

Sample Program 7.1//A program to find length of a given string.#include #include #include void main()


46

{char s[80];int ln;printf(Enter any string :);gets(s);ln=strlen(s);printf(\n\t Length of %s is %d,s,ln);getch();

}

2. strcpy( ): it is used to copy a string to another. Means we can copy source string to targetstring

eg. char s1[10]=India,s2[10];strcpy(s2,s1);

Sample Program 7.2//A program to copy a given string to another strings#include #include #include void main(){

char s1[80],s2[80];printf(Enter any string:);gets(s1);strcpy(s2,s1);printf(\n\t Copy of %s is %s,s1,s2);getch();

}3. strcmp( ): This function is used to compare two strings and accordingly returns the val-ue. That is, it returns the numerical difference between the strings. This function is case-sensitive func-tion. It takes the following general form:

strcmp(string1, string2);Here, string1 and string2 may be string variables or strings constants. The function will compare thestrings and returns the value. If this value is 0, implies that both the strings are equal. If it is positive,implies that string1 is greater and if negative, implies that string2 is greater. For example:

strcmp(city1, city2);strcmp(Pune, city1); etc.

Sample Program 7.3//A program to compare two string and find the largest string among them.#include #include #include void main(){

char s1[80],s2[80];printf(Enter First string :);gets(s1);printf(Enter Second string :);gets(s2);if(strcmp(s1,s2) == 0)

printf(\n\t %s is equals to %s,s1,s2);else if(strcmp(s1,s2) > 0)

printf(\n\t %s is larger than %s,s1,s2);else if(strcmp(s1,s2) < 0)

printf(\n\t %s is larger than %s,s2,s1);getch();


47

}4. strrev( ): it is used to reversed a string.

eg. char s1[10]=India;strrev(s1);

above function code will reverse string India to aidnI

Sample Program 7.4//A program to reverse a string a given string#include #include #include void main(){

char s[80];clrscr();printf(Enter any string :);gets(s);printf(\n\t Original String is %s, s);strrev(s);printf(\n\t Its reverse string is %s ,s);getch();

}5. strupr( ): it converts a lower case string to its equivalent upper case string.

eg. char s1[10]=india;strupr(s1);

above function will prints upper case string. As INDIA on screen

Sample Program 7.5//A program to convert a lower case string to its equivalent upper case string#include #include #include void main(){

char s[80];int ln=0;printf(Enter a string below\n);gets(s);printf(\n\t Entered lower case string is %s,s);strupr(s);printf(\n\t Converted String is %s ,s);getch();

}6. strlwr( ): it converts upper case string to its equivalent lower case string.

eg. char s1[10]=BARODA;strlwr(s1);

above command will convert upper case string BARODA to baro-da

Sample Program 7.6//A program to convert a upper case string to its equivalent lower case string#include #include #include void main(){

char s[80];int ln=0;


48

printf(Enter any string :);gets(s);printf(\n\t Entered lower case string is %s,s);strlwr(s);printf(\n\t Converted String is %s ,s);getch();

}7. strcat( ): This function joins two strings together. That is, this function is used to

concatenate the strings. It takes the following general form:strcat(string1, string2);

here, string1 and string2 are character arrays. When this function is executed, content of string2 isattached at the end of string1. Content of string2 remains unchanged.

Sample Program 7.7// A program to append a string to another string#include #include #include void main(){

char s1[80], s2[80];clrscr();printf(Enter first string :);gets(s1);printf(Enter second string : );gets(s2);strcat(s1,s2);printf(\n\t Converted String is %s ,s);getch();

}Above program will append second string at the end of the first string. similarly you can developed logicfor all the function

Additional programsSample Program ad1:// Reading a line of text from terminal#include #include void main(){

char line[81], character;int c=0;clrscr();printf(Enter text, press at end\n);do{

character = getchar();line[c] = character;c++;

} while(character != \n);

c = c-1;line[c]=\0;printf(\n\t%s, line);getch();

}


49

Sample Program ad2:// Sort a list of string in alphabetical order#include #include void main(){

char string[5][20], dummy[20];int i=0, j=0;clrscr();printf(Enter the name of five items \n);while(i < 5)

scanf(%s,string[i++]);for(i=1; i 0){

strcpy(dummy,string[j-1]);strcpy(string(string[j-1],string[j]);strcpy(string[j],dummy);

}}

}printf(\n\t Alphabetical list of items\n);for(i=0; i


50

CHAPTER - 8

FUNCTIONS IN C LANGUAGE

A function is self-contained block of statements that performs particular task. C functionscan be classified into two types:

1) Library functions (Built-in Functions)2) User-defined functionsThe library functions are the functions which are already defined in Cs functions library i.e.

header files. For example, the functions scanf() and printf() are the library functions defined in filestdio.h same as functions sqrt() is defined in math.h and getch() is defined in conio.h. User definedfunction is the function defined by the programmer who has written the program. The task to per-form is decided by the user. For example, the main() function is an user-defined function. We decidewhat is to be written in this function.

Need of user-defined function1. The functional program facilitates top-down modular programming approach.2. The length of source program can be reduced by using functions at appropriate places.3. It is easy to locate and isolate a faulty function for further investigations.4. A function may be used by many other programs. This means that a C programmer can build on whatothers have already done. That is we can reuse the functions already defined in some program files.user-defined function

In order to make use of user defined functions, we need to establish three elements that arerelated to functions.

1. Function definition2. Function call3. Function declaration

1. Declaration of a functionSyntax:

Return-type name_of_function(list of arguments);Example:

int length(char ch);float factorial(int);

A function has four type of declaration according to it type. There are four type of function declarationNo return value no argument; means a function will not return any value or it will not accepting argumentsform user.Eg. void sumNo(void);

No return value with argument, means a function will not return value but it will accept one or more thenone arguments for process.Eg. void sumNo(int, int)Above function will not return any value but it will accept two integer type arguments.

With return value with no argument, means a function will return a value but never accept anyargument from userEg. int sumNo(void);

With return value with arguments, means a function will return a value and it also accepts one or morethen one arguments for process.Eg. int sumNo(int, int);A declaration of a function is known as a prototype of a function.


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2. Function definitionThe function definition is an independent program module that is specially written to implement therequirements of the function. So it is also called as function implementation.Syntax:

Return_type function_name(parameters list){

local variables declaration;statements;- - - - - -;- - - - - -;return statement;

}It includes three parts:

1. Function typeIt specifies type of the value that the function is expected to return to the program calling thefunction. It is also called as return type. If function is not returning any values we have tospecify it as void.

2. Function nameIt is any valid C identifier name and therefore must follow the rules for creation of variable namesin C.

3. Parameters listIt declares variables that will receive the data sent by the calling program. They serve asinput data to the function to carry out specific task. Since, they represent the actual input valuesthey are referred as formal parameters or formal arguments.

Example:float mul(float x, float y){

float result; /* local variable */result = x * y; /* find the result */return(result); /* return the result */

}Return values

A function may or may not send back any value to the calling function. If it does, it is done byreturn statement. The return statement also sends the program control back to the callingfunction. It is possible to pass a calling function any number of values but called function canonly return one value per call.

3. Function callA function can be called by simply using function name followed by a list of actual parameters (or ar-guments) if any, enclosed in parentheses.Example:

main(){

float m;m = mul(5.2, 3.71); /* function call */printf(\n%d,m);

}When compiler encounters the function call, it transfers program control to the function

mul() by passing values 5.2 and 3.71 (actual parameters) to the formal parameters on the functionmul(). The mul() will performs operations on these values and then returns the result. It will be storedin variable m.


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Sample Program 8.1// A function with no return no arguments#include #include void main(){

void sumNo(void); // Declaration of a function / Prototype of a functionclrscr();sumNo(); // Calling a function.getch();

}

void sumNo(void) // function Definition{

int n1, n2, n3;

printf(Enter value to N1: );scanf(%d,&n1);


n3=n1+n2;

printf(\n\t Sum is %d, n3);}Sample Program 8.2:// A function with no return with arguments#include #include void main(){

int n1, n2;void sumNo(int, int); // Declaration of a function / Prototype of a functionclrscr();


printf(Enter value to N2: );scanf(%d,&n2);sumNo(n1,n2); // Calling a function.getch();

}void sumNo(int x, int y) // Body of a function{

int z;z=x+y;printf(\n\t Sum is %d, z);

}Sample Program 8.3// A function with return type and no arguments.


int n3;


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int sumNo(void); // Declaration of a function / Prototype of a functionclrscr();n3=sumNo(); // Calling a function.printf(\n\t Sum is %d, n3);getch();

}int sumNo(void) // Body of a function{

int n1,n2;printf(Enter value to N1: );scanf(%d,&n1);

printf(Enter value to N2: );scanf(%d,&n2);return (n1+n2);

}Sample Program 8.4// A function with return with arguments


int n1,n2,n3;int sumNo(int,int); // Declaration of a function / Prototype of a functionclrscr();



n3=sumNo(n1,n2); // Calling a function.

printf(\n\t Sum is %d, n3);

getch();}

int sumNo(int x,int y) // Body of a function{

int z;return (z);

}

Similarly you can developed function for subtraction, multiplication, and division of two numbers. Forabove mentioned type.A function may called with reference to value is known as called by value, where as when a function iscalled with reference to address of a variable is known as called by reference.In called by value type of function calling we send a copy of a variable to the called function. Where as incalled by reference we send the address of variable.


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Recursive functionWhen a function calls itself within the same function is called as recursion of a function. A recur-

sive function is more efficient then a normal function. It provide faster process.

Sample Program 8.5/*A Program using recursive functionFind a factorial number of a given number.*/#include #include void main(){

long n=0,f=0;long factorial(long); // Declaration of a function / Prototype of a functionclrscr();printf(Enter value to N: );scanf(%ld,&n);f=factorial(n); // Calling a function.printf(\n\t %ld! = %ld, n,f);

getch();}long factorial(long n) // Body of a function{

long f=1;if(n==1)

return 1;else

f=n * factorial(n-1);

return f ;}

Exercise of a functionWrite a function to find square root of a given number.Write a function to find square of a given number.write a function to convert temperature entered in Celsius degree to its equivalent Fahrenheit.Write a function to print first n fibbonacy number.Write a function to find circumference and area of a circle with given radiusWrite a function to find distance entered in km to it equivalent meter, feet and inches.Write a function to convert Indian currency to its equivalent dollar, and pound and vise versa.Write a function to swap a value of variables.Write a function to calculate number of words, characters, digits in a given string.Write a function to remove extra spaces from given string.Write a function to reverse a string.Write a function to check whether entered character is vowel or not.Write a function to check whether entered year is leap year of not.Write a function to check whether a entered number is odd of even.


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Additional ProgramsSample program ad1Function to find compound interest (no return no argument)#include #include void main(){

clrscr() ;void printline();void value();void printline();printline();value();printline();getch();

}

void printline(){

int i;for(I=1;I


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printline();print( %12.2f,sum);getch();

}void printline(){

int i;for(I=1;I


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CHAPTER 9

POINTERS IN C

A pointer is a variable capable of holding address of another variable. A pointer provides fasterprocess as well as variables that are not accessible to the function that also can be accessed through thefunction. Pointer variable occupies less memory means it occupy only two bytes in memory. It also usedto developed system programs like virus, anti-virus, operating system etc. A pointer is denoted by * sign.

We can declare a pointer variable same as normal variable but we must put * sign before a varia-ble to indicate pointer variable.Syntax:

dataType *name_of_pointervariable;Example:

int *p;char *ptr;

The address can be collected in a variable, by ,p = &i;here, p is not an ordinary variable. It is a pointer variable that contains the address of other integer varia-ble ( i ).

Sample Program of pointer variable 9.1// Write a program to inter change value of two variable.


int n1, n2, t, *p1, *p2;clrscr();

p1=&n1; //Storing address of n1 to p1;p2=&n2; //Storing address of n2 to p2;

printf(Enter value to N1: );scanf(%d, &n1);

printf(Enter value to N2: );scanf(%d, &n2);

printf(\n\t Before Swapping value of n1 and n1 );pritnf\n\t N1 = %d,n1);pritnf\n\t N2 = %d,n2);

t=*p1;*p1=*p2;*p2=t;

printf(\n\t After Swapping value of n1 and n1 );pritnf\n\t N1 = %d,n1);pritnf\n\t N2 = %d,n2);getch();

}Generally we can use a pointer for a different purpose for e.g. pointing to an array, a array of a pointersetc.


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Pointer to an array:Pointer to an array is that a pointer variable points to an array. A pointer variable holds address of

the first elements of an array which is known as base address. Then after we can manipulate an arrayusing pointer.Syntax:

int n[5]={0}, *p1p1=n;

Here p1 holds the address of first element of an array. This address of first element is known as baseaddress. A sample program shows use of pointers with an array.

Sample Program 9.2// Program to accept five value to an array and print it with the help of array.#include #include void main(){

int n[5], i, *p1;clrscr();

p1=n;

printf(Enter five values to an array\n);for(i=0; i


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scanf(%d,n2);

printf(\n\t Output of variables using array of pointer\n);for(i=0; i


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CHAPTER 10

STRUCTURE AND UNION

A structure is a collection of different types of variables which are known as member of a struc-ture. An advantage of the structure is that we can store different types of values. Generally a normal arraycan hold more than one variable of similar type, where a structure can hold more than one variable of dif-ferent size. A structure can be defined with struct clause. A structure member can occupy individualmemory location.Declaring a StructureSyntax:

struct StructureName{

member1;member2;memberN;

};Example:

struct book{

char name[20] ;float price;int pages;

};This statement defines a new data type called struct book. Each variable of this data type will consist ofa character variable name, a float variable called price and integer variable called pages. Once the newstructure data type has been defined one or more variables can be declared to be of that type. For exam-ple the variables b1, b2, b3 can be declared to be of the type struct book, as,

struct book b1,b2,b3;

This statement sets aside space in memory. It makes available space to hold all the elements in the struc-ture.We can combine the declaration of the structure type and the structure variables in one statement.For example,

struct book{

char name[20] ;float price;int pages;

};struct book b1,b2,b3;

is same asstruct book

{char name[20] ;float price;int pages;

} b1,b2,b3;Or evenstruct

{char name[20] ;float price;


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int pages;}b1,b2,b3;

Like variables and array, structure variables can also be initialized where they are declared. The formatused is quite similar to that used to initiate arrays.struct book

{char name[20] ;float price;int pages;

};struct book b1 = { Basic, 130.00,550};struct book b2 = { Physics, 150.00,300};

Accessing a structure ElementsIn arrays we can access individual elements of an array using a subscript/index. Structures use a differentscheme. They use a dot (.) operator. So to refer to pages of the structure defined above example, wehave to use,b1.pages

similarly, to refer to price we would use,b1.price

Note that before the dot there must always be a structure variable and after the dot there must always bea structure element.

Sample Structure Program 10.1/* Declare a structure of a student which has following member rno, name, address, city, acceptdata from user and print it. */#include #include struct student{

int rno;char name[10],address[15],city[20];

};void main(){

struct student s1;clrscr( );

printf(Enter Rollno: );scanf(%d,&s1.rollno);flushall( );

printf(Enter Name: );gets(s1.name);flushall();

printf(Enter Address: );gets(s1.address);flushall( );

printf(Enter City: );gets(s1.city);flushall( );

printf(\n\t Rollno: %d,s1.rollno);


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printf(\n\t Name: %s,s1.name);printf(\n\t Address: %s,s1.address);printf(\n\t City: %s,s1.city);getch();

}similarly we can also define a pointer to a structure, a pointer to a structure is quite efficient and occupiesonly two byte in memory, where as a structure occupies memory as the size of structure.Syntax:

struct student *s1;to access member of a structure we have to use -> (arrow) operator like s1->rollno and so on.We can also declare a structure array variable to store more then one value.syntax:

sturct student s1[5];

above notation can store details of five student.Sample structure program 10.2/* Declare a structure of a student which has following member rno, name, address, city, acceptdata from user and print it. Use structure array. */#include #include struct student{


};void main(){

int i;struct student s[3];clrscr();for(i=1; i


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}

similarly we can assign a pointer to structure object variable

Sample structure program 10.3/* Declare a structure of a student which has following member rno, name, address, city, acceptdata from user and print it. Use pointer variable */#include #include struct student{


};void main(){

int I;struct student s1,*s;clrscr();

s=&s1;printf(Enter Rollno: );scanf(%d,&s->rollno);flushall();

printf(Enter Name: );gets(s->name);flushall();

printf(Enter Address: );gets(s->address);flushall();printf(Enter City: );gets(s->city);flushall();

printf(\n\t Rollno: %d,s->rollno);printf(\n\t Name: %s,s->name);printf(\n\t Address: %s,s->address);printf(\n\t City: %s,s->city);

getch();}similarly we can assign a pointer to structure object variable which an array type.

Sample Structure Program 10.4/* Declare a structure of a student which has following member rno, name, address, city, acceptdata from user and print it. Use structure array and pointer variable */#include #include struct student{


};void main(){

int i;


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struct student s1[2],*s;clrscr();

s=&s1;

for(i=0;irollno);flushall();

printf(Enter Name: );gets(s->name);flushall();

printf(Enter Address: );gets(s->address);flushall();

printf(Enter City: );gets(s->city);flushall();

}

s=&s1[0];for(i=0;irollno);printf(\n\t Name: %s,s->name);printf(\n\t Address: %s,s->address);printf(\n\t City: %s,s->city);

}getch();

}

Union:Union is quite similar to a structure but the different is that a structure member can store an indi-

vidual memory location, where a union member can share

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