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Switch case And Looping Submitted by: Mark Kazuyoshi P. Asoi
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Page 1: Mark asoi ppt

Switch case And

Looping

Submitted by:Mark Kazuyoshi P. Asoi

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Programming is instructing a computer to do something for you with the help of a Programming language. The role of a Programming language can be described in two ways:

Technical: It is a means for instructing a Computer to perform TasksConceptual: It is a framework within which we organize our ideas about things and processes.

We first define the word “Programming”, it is a computer language programmers use to develop applications, scripts, or other set of instructions for a computer to execute. 

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Computer Programming  (often shortened to  Programming  or coding) is the process of designing, writing, testing, debugging, and maintaining the source code of computer programs. This source code is written in one or more  Programming Language (such as Java, C++, C#, Python, etc.). The purpose of Programming is to create a set of instructions that computers use to perform specific operations or to exhibit desired behaviors. The process of writing source code often requires expertise in many different subjects, including knowledge of the application domain, specialized algorithms and formal logic.

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As an individual, I have learned that Programming is a very broad because it composes many scripts, applications and can be used to run a program that has been part of the programming language.

The distinction between data and procedures is not that clear cut. In many Programming languages, procedures can be passed as data (to be applied to “real” data) and sometimes processed like “ordinary” data. Conversely ``ordinary'' data can be turned into procedures by an evaluation mechanism.

A Programming language should both provide means to describe primitive data and procedures and means to combine and abstract those into more complex ones.

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Programming is a creative process done by programmers to instruct a computer on how to do a task. Programming languages let you use them in different ways, e.g adding numbers, etc… or storing data on disk for later retrieval.

At first, Programming is confusing because you have so much to understand about codes that will enable to run a program. Programming has applications and program development, the best example for this is the Internet browser…

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New to Programming or thinking about it? It might surprise you to know that there are many programmers who program just for fun and it can lead to a job.

You have to consider languages to run or write your own program, most demanded language in Programming is the DEV C++ (a full-featured Integrated Development Environment (IDE)).

C++ is one of the most used Programming languages in the world. Also known as "C with Classes". 

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Within software engineering, Programming (the implementation) is regarded as one phase in a software development process.There is an ongoing debate on the extent to which the writing of programs is an art form, a craft or an engineering discipline.] In general, good Programming is considered to be the measured application of all three, with the goal of producing an efficient and evolvable software solution (the criteria for "efficient" and "evolvable" vary considerably). The discipline differs from many other technical professions in that programmers, in general, do not need to be licensed or pass any standardized (or governmentally regulated) certification tests in order to call themselves "programmers" or even "software engineers." Because the discipline covers many areas, which may or may not include critical applications, it is debatable whether licensing is required for the profession as a whole. In most cases, the discipline is self-governed by the entities which require the Programming, and sometimes very strict environments are defined (e.g. United States Air Force use of AdaCore and security clearance). However, representing oneself as a "Professional Software Engineer" without a license from an accredited institution is illegal in many parts of the world.

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Another ongoing debate is the extent to which the  Programming language used in writing computer programs affects the form that the final program takes. This debate is analogous to that surrounding the Sapir–Whorf hypothesis in linguistics and cognitive science, which postulates that a particular spoken language's nature influences the habitual thought of its speakers. Different language patterns yield different patterns of thought. This idea challenges the possibility of representing the world perfectly with language, because it acknowledges that the mechanisms of any language condition the thoughts of its speaker community.

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Switch CaseSwitch case statements are a substitute for long if statements that compare a variable to several "integral" values ("integral" values are simply values that can be expressed as an integer, such as the value of a char).

but there is really very little left to know about Programming itself. Most of the rest of C is concerned with making the business of Programming simpler. A good example of this is the switch construction.

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basic format for using switch case

switch ( <variable> ) {case this-value: Code to execute if <variable> == this-value break;case that-value: Code to execute if <variable> == that-value\ break;...default: Code to execute if <variable> does not equal the value following any of the cases break;}

The value of the variable given into switch is compared to the value following each of the cases, and when one value matches the value of the variable, the computer continues executing the program from that point.

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The condition of a switch statement is a value. The case says that if it has the value of whatever is after that case then do whatever follows the colon.

The break is used to break out of the case statements. An important thing to note about the switch statement is that the case values may only be constant integral expressions.

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Break is a keyword that breaks out of the code block, usually surrounded by braces, which it is in. In this case, break prevents the program from falling through and executing the code in all the other case statements.

The default case is optional, but it is wise to include it as it handles any unexpected cases. Switch statements serves as a simple way to write long if statements when the requirements are met. Often it can be used to process input from a user.

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This shows how would you use a Switch in a Program#include <iostream>

using namespace std;

void playgame(){ cout << "Play game called";}void loadgame()} cout << "Load game called";void playmultiplayer(){ cout << "Play multiplayer game called";}

int main(){ int input;

cout<<"1. Play game\n"; cout<<"2. Load game\n"; cout<<"3. Play multiplayer\n"; cout<<"4. Exit\n"; cout<<"Selection: "; cin>> input; switch ( input ) { case 1: // Note the colon, not a semicolon playgame(); break; case 2: // Note the colon, not a semicolon loadgame(); break; case 3: // Note the colon, not a semicolon playmultiplayer(); break; case 4: // Note the colon, not a semicolon cout<<"Thank you for playing!\n"; break; default: // Note the colon, not a semicolon cout<<"Error, bad input, quitting\n"; break; } cin.get();}

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That program will compile, but cannot be run until the undefined functions are given bodies, but it serves as a model (albeit simple) for processing input. If you do not understand this then try mentally putting in if statements for the case statements. Default simply skips out of the switch case construction and allows the program to terminate naturally. If you do not like that, then you can make a loop around the whole thing to have it wait for valid input. You could easily make a few small functions if you wish to test the code.

but there is really very little left to know about Programming itself. Most of the rest of C is concerned with making the business of Programming simpler. A good example of this is the switch construction.

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LoopingLoops are used to repeat a block of code. Being able to have your program repeatedly execute a block of code is one of the most basic but useful tasks in Programming -- many programs or websites that produce extremely complex output (such as a message board) are really only executing a single task many times.

In a loop structure, the program asks a question, and if the answer requires an action, it is performed and the original question is asked again until the answer is such that the action is no longer required.

In a loop structure, the program asks a question, and if the answer requires an action, it is performed and the original question is asked again until the answer is such that the action is no longer required.

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(They may be executing a small number of tasks, but in principle, to produce a list of messages only requires repeating the operation of reading in some data and displaying it.) Now, think about what this means: a loop lets you write a very simple statement to produce a significantly greater result simply by repetition.

One Caveat: before going further, you should understand the concept of C++'s true and false, because it will be necessary when working with loops (the conditions are the same as with if statements).

Three types of Loops:for, while, and do..

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For ( variable initialization; condition; variable update ) { Code to execute while the condition is true}

FOR

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The variable initialization allows you to either declare a variable and give it a value or give a value to an already existing variable. Second, the condition tells the program that while the conditional expression is true the loop should continue to repeat itself. The variable update section is the easiest way for a for loop to handle changing of the variable. It is possible to do things like x++, x = x + 10, or even x = random ( 5 ), and if you really wanted to, you could call other functions that do nothing to the variable but still have a useful effect on the code.

Notice that a semicolon separates each of these sections, that is important. Also note that every single one of the sections may be empty, though the semicolons still have to be there. If the condition is empty, it is evaluated as true and the loop will repeat until something else stops it.

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This program is a very simple example of a for loop. x is set to zero, while x is less than 10 it calls cout<< x <<endl; and it adds 1 to x until the condition is met. Keep in mind also that the variable is incremented after the code in the loop is run for the first time.

#include <iostream>

using namespace std; // So the program can see cout and endl

int main(){ // The loop goes while x < 10, and x increases by one every loop for ( int x = 0; x < 10; x++ ) { // Keep in mind that the loop condition checks // the conditional statement before it loops again. // consequently, when x equals 10 the loop breaks. // x is updated before the condition is checked. cout<< x <<endl; } cin.get();}

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WHILEThe basic structure:

While ( condition ) { Code to execute while the condition is true } The true represents a boolean expression which could be x == 1 or while ( x != 7 ) (x does not equal 7). It can be any combination of boolean statements that are legal. Even, (while x ==5 || v == 7) which says execute the code while x equals five or while v equals 7. Notice that a while loop is the same as a for loop without the initialization and update sections. However, an empty condition is not legal for a while loop as it is with a for loop.

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#include <iostream>

using namespace std; // So we can see cout and endl

int main(){ int x = 0; // Don't forget to declare variables

while ( x < 10 ) { // While x is less than 10 cout<< x <<endl; x++; // Update x so the condition can be met eventually } cin.get();}

The easiest way to think of the loop is that when it reaches the brace at the end it jumps back up to the beginning of the loop, which checks the condition again and decides whether to repeat the block another time, or stop and move to the next statement after the block.

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do {} while ( condition ) ;

The Structure:

DO.. WHILE

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The condition is tested at the end of the block instead of the beginning, so the block will be executed at least once. If the condition is true, we jump back to the beginning of the block and execute it again.

A do.. while loop is basically a reversed while loop. A while loop says "Loop while the condition is true, and execute this block of code", a do.. while loop says "Execute this block of code, and loop while the condition is true".

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#include <iostream>

using namespace std;

int main(){ int x; x = 0; do { // "Hello, world!" is printed at least one time // even though the condition is false cout<<"Hello, world!\n"; } while ( x != 0 ); cin.get();}

Keep in mind that you must include a trailing semi-colon after the while in the above example. A common error is to forget that a do..while loop must be terminated with a semicolon (the other loops should not be terminated with a semicolon, adding to the confusion). Notice that this loop will execute once, because it automatically executes before checking the condition.

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Condition and Explanation of the Programs that have been tested

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#include <stdlib.h>#include <stdio.h>

int main(void) { int n; printf("Please enter a number: "); scanf("%d", &n); switch (n) { case 1: { printf("n is equal to 1!\n"); break; } case 2: { printf("n is equal to 2!\n"); break; } case 3: { printf("n is equal to 3!\n"); break; } default: { printf("n isn't equal to 1, 2, or 3.\n"); break; } } system("PAUSE"); return 0;}

Switch case 1

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#include <stdio.h>

main() { int grade; printf ("Input grade :"); scanf("%d", & grade);

switch (grade) {

case 1: printf("Fall (F)\n");break; case 2: printf("Bad (D)\n");break; case 3: printf("Good (C)\n");break; case 4: printf("Very Good (B)\n");break; case 5: printf("Excellent (A)\n");break; default: printf("You have inputted false grade\n"); break; // break isn’t necessary here }}

Switch case 2

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#include <iostream>

using namespace std;

int main ()

{

int score;

cout << "What was your score?";

cin >> score;

if (score <= 25)

{

cout << "\nOuch, less than 25...!";

}

else if (score <= 50)

{

cout << "\nYou score aint great mate..";

}

else if (score <= 75)

{

cout << "\nYour pretty good, wel done man!";

}

else if (score <= 100)

{

cout << "\nYou got to the top!!!";

}

else {

cout << "\nYou cant score higher than 100!!! Cheater!!!!";

} cin.ignore();

cin.get();

return 0;

}

Switch case 3

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#include <iostream>using namespace std;int main(void){ char grade; cout << "Enter your grade: "; cin >> grade; switch (grade) { case 'A': cout << "Your average must be between 90 - 100" << endl; break; case 'B': cout << "Your average must be between 80 - 89" << endl; break; case 'C': cout << "Your average must be between 70 - 79" << endl; break; case 'D': cout << "Your average must be between 60 - 69" << endl; break; default: cout << "Your average must be below 60" << endl; } return 0;}

Switch case 4

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#include <stdio.h>#include <math.h>

main() {

int i, n, prime=1; // prime is true printf("Input natural number :"); scanf("%d", &n); for( i=2; i<= n-1; i++) { if( n % i == 0 ) { // also possible to state if(!(n % i))

prime =0; // prime is now false break;

} } if( prime )

printf("%d is prime number !\n", n); else

printf("%d isn’t prime number!\n", n);

}

Switch case 5

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#include <iostream> using namespace std; // So the program can see cout and endl int main(){ // The loop goes while x < 10, and x increases by one every loop for ( int x = 0; x < 10; x++ ) { // Keep in mind that the loop condition checks // the conditional statement before it loops again. // consequently, when x equals 10 the loop breaks. // x is updated before the condition is checked. cout<< x <<endl; } cin.get();}

Looping Statement 1

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#include <stdio.h>

main()

{ float price;

short quantity;

char answer;

do

{ printf("Enter 'price quantity': ");

scanf("%f %hi", &price, &quantity);

printf("The total for this item is $%6.2f.\n", price * quantity);

printf("Another (Y/N)? ");

scanf(" %c", &answer);

}while ("answer == 'Y' | | answer == 'y'");

printf("Thank you for your patronage.\n");

}

Looping Statement 2

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#include <stdio.h>

main()

{ float price;

short quantity;

char answer;

printf("Do you wish to enter a purchase (Y/N)? ");

scanf(" %c", &answer);

while ("answer == 'Y' | | answer == 'y'")

{ printf("Enter 'price quantity': ");

scanf("%f %hi", &price, &quantity);

printf("The total for this item is $%6.2f.\n", price * quantity);

printf("Another (Y/N)? ");

scanf(" %c", &answer);

}

printf("Thank you for your patronage.\n");

}

Looping Statement 3

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#include<iostream>using namespace std;

int main(){ int n; cout<<"Enter the starting number>"; cin>>n; while(n>0){ cout<<n<<","; --n; } cout<<"FIRE!\n"; return 0; }

Looping Statement 4

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// // Demonstrates do while

#include <iostream.h>

int main() { int counter; cout << "How many hellos? "; cin >> counter; do { cout << "Hello\n"; counter--; } while (counter >0 ); cout << "Counter is: " << counter << endl; return 0; }

Looping Statement 5

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An Output Program using Dev C++

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Because of so many experiences I had before this program run, I found Programming is also interesting for the more you are practicing to make a program run, the more questions that came up in my mind and try something that will fit to this or entering new codes to make matrix etc… that I know is possible.

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In this switch case missing out a break statement causes control to fall through to the next case label. Switches can always be replaced by nested if-else statements, but in some cases this may be more clumsy. Each break statement terminates the enclosing switch statement. Control flow continues with the first statement 

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The switch statement can include any number of case instances, but no two case constants within the same switch statement can have the same value. Execution of the statement body begins at the selected statement and proceeds until the jump-statement transfers control out of the case body.

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Unlike if-then and if-then-else statements, the switch statement can have a number of possible execution paths, A switch works with the byte, short, char, and int primitive data types.

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Switch case is substitute for long if statements that compare a variable to several "integral" values that can be expressed as an integer,

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When I learned that Programming is very sensitive and at the same time very detailed when it comes to entering codes, I make sure that it is clear means that I put everything important codes in it so that the program would run.

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I noticed that sometimes if the program does not run, it is because some braces are not included and I accidentally put braces on the same line and it causes the program not to read its contents. Programming is sensitive, when there is missing variable or braces or some words it does not run.

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Being able to have your program repeatedly execute a block of code is one of the most basic but useful tasks in Programming

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I have came up with this by just starting to write this code: #include <iostream> and then enter the succeeding codes, compiled and run.

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The do...while loop executes the body of the loop before its condition is tested and ensures that the body always executes at least one time. What if you want to ensure that Hello is always printed at least once? The while loop can't accomplish this, because the if condition is tested before any printing is done. You can force the issue with an if statement just before entering the while:

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Submitted to:Professor.

Erwin Globio

 http://eglobiotraining.com/

Official Website: