Dot NET Fundamentals Part2

8/10/2019 Dot NET Fundamentals Part2

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An introduction to C#

C# is a language that was developed by Microsoft

specifically targeted for the .NET platform.


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C# Features

No pointers

Automatic memory management

Completely object-oriented

Supports interface-based programming

Both implementation inheritance and interfaceinheritance supported

Support for overloaded operators

Support for aspect-based (attribute-based)programming

Can only produce managed-code


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Lets try a simple program.


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Create a Working Directory

mkdir k:\week1\hello

Copy corvars.bat

copy

c:\Program Files\Microsoft Visual Studio.NET

\FrameworkSDK\bin\corvars.bat

k:\week1\hello\corvars.bat

Set up environment, run covars.bat

Cd k:\week1\hello

Type corvars.bat


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Open notepad, create the following fi le and

save it in the k:\week1\hel lo directory ashello.cs.

class Hello

{

static void Main()

{

System.Console.WriteLine("Hello World");

}

}


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Compile the program

k:\week1\hello>csc Hello.cs

Run the programK:\week1\hello>Hello.exe

K:\week1\hello> Hello World


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C#.NET Language Basics

Types in C#

Defining integer types

A Bit About Strings

Reading From and Writing To The Console

If Then Statement

LoopingThe For Next Statement


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Primitive Types

C# Type .NET Framework type

bool System.Boolean

byte System.Byte

sbyte System.Sbyte

char System.Char

decimal System.Decimal

double System.Double

float System.Single


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Primitive Types (contd.)

int System.Int32

uint System.UInt32

long System.Int64

ulong System.UInt64

object System.Object

short System.Int16

ushort System.UInt16

string System.String


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A word on types

All types in .NET derive from System.Object

They are provided implementations of ToString() and

GetType() To get a string with the type of any variable, you can

call .GetType()

Whenever you call Console.WriteLine(obj) the

ToString() method on objis implicitly called. Thedefault ToString implementation for classes simplyreturns the name of the class.


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What Are I ntegers

0, 432, -5, 10000000, -10000000

Integers are whole numbers

Integervariables are stored as signed 32-bit

(4-byte) integers ranging in value from -2,147,483,648 through 2,147,483,647.


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Defining Integers

int i;

int i, j, k;

int i = 12;

j = i;

j is now equal to 12i = 15;

k = i + j; k is equal to 27

To write an Integer, convert it to a String using:

k.ToString();


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A Bit About Str ings


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What are str ings?

abcdef Abcdef aBcdEf A23+-/*789 qJohn J. Smith

How do you do?

123 South Street, Calais, ME 04235 Are we there?

an empty string


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How do we define str ings?

string strTmp;

strTmp = time will tell;

string strTmp = time will tell;

strTmp = Console.ReadLine();

string strTmp2;

strTmp2 = strTmp;

strTmp2time will tell


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Concatenating Str ings

string strCity = Calais;

string strState = ME;

string strZip = 04270;string strLoc;

strLoc = strCity + , + strState + + strZip;

strLocCalais, ME 04270


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Some Str ing Functions

string strTmp;

strTmp.Trim();removes leading and trailing spaces

strTmp.ToUpper();converts string to all upper case

strTmp.ToLower();converts string to all lower case

strTmp.Length;returns string length as an integer

strTmp.SubString()extracts a substring


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Str ing Function Examples

string strTmp = Hello World ;

strTmp.Trim();

strTmp

Hello World

string strTmp = Hello World;

strTmp.ToLower(); hello world

strTmp.ToUpper(); HELLO WORLD


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String.Length Function

string strTmp;

strTmp = in the beginning;

The value of strTmp.Length is 16.int i;

i = strTmp.Length;

The value of i is 16.


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Str ing.SubStr ing() Function

String.Substring(startIndex , length );

Parameters (are Integers)

startIndexWhere the substring starts.startIndex is zero-based.

lengthThe number of characters in the substring.


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Substr ing Examples

string strTmp;

strTmp = around the world;

strTmp.Substring(0,6);

aroundstrTmp.Substring(11,5);world

strTmp.Substring(0,strTmp.Length);

around the world


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Writing to the Console

Console.WriteLine(String); write with line return

Console.WriteLine(Hi There)

C:\>Hi There

C:\>

Console.Write(String);write with no line return

Console.Write(Hi There)C:\>Hi There


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Reading from the Console

Console.ReadLine();returns a string

string tmp;

Console.Write(What is your name? );

tmp = Console.ReadLine();

Console.WriteLine(Hi + tmp);

C:\>What is your name? ChipC:\>Hi Chip

C:\>


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i f Statement

if (some condition is true)

{

do something in here,

using one or more lines of code

}


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What is difference between = and ==?

= is for assignment of value

String tmpString = Hello world;

int i = 12;

== is for equivalence

if (str1 == str2) { some code }if (str.Length == 0) { some code }

if (str1 != end) { some code }


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Sample if Statement

string strInput ;

strInput = Console.ReadLine();

if (strInput == )

{

Console.WriteLine(Input required.);

}


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The For Loop


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A Simple For Loop

int i;for (i = 1; i


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Or You Could Reverse It

int i;for (i = 10; i>0; i--)

{

Console.WriteLine("The value of i is " + i.ToString());

}

The Value of i is 10

The Value of i is 9

The Value of i is 8

The Value of i is 2

The Value of i is 1


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To Walk Through a Str ing

string tmp = hello world;

for (int k = 0; k< tmp.Length-1;k++)

{

Console.WriteLine(tmp.Substring(k,1));

}


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To Walk Through a Str ing Backward

string tmp = "hello world";

for (int k =tmp.Length-1;k>-1;k--)

{

Console.WriteLine(tmp.Substring(k,1));

}


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What About?

What If We Want To Enter More Data?

What If No String Is Entered?What If The Entered String Is Too Long?

How Do We Know When We Are Done?


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What I f We Want To Enter More Data?

LabelsA Label is Defined with a Colon ReturnHere:

goto Statements

goto Statements Direct Program Flow To A Label

goto ReturnHere;

GoTo Statements are Evil and High Risk!!!


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What I f No Str ing I s Entered?

Checking for a zero length string.

if (tmpStr.Length == 0)

{

Console.WriteLine(No String Entered);

goto ReturnHere;

}

Note: You could also check for tmpStr ==


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What I f The Entered Str ing I s Too Long?

Lets only work with strings up to 10 characters

if (strTmp.Length > 10)

{

strTmp = strTmp.SubString(0,10);

}


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How Do We Know When We Are Done?

Lets check for the string end to end the program

if (strTmp == end)

{

return;}

Note: return tells the program to exit the subroutine, which in this

case will end the program.


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Comments in C#

Both /* */ and // can be used for comments.

VS provides comment/uncomment selections.

Use the menu bar, or Ctrl-K Ctrl-C for comment and Ctrl-K Ctrl-U for uncomment


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Now lets redo hello.cs as a

Visual Studio project.


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Visual Studio.NET

The newest version of Visual Studio

Multiple language development finally in oneenvironment.

Can program in

Visual C#

Visual Basic.NET

Visual C++.NET

Can build

Desktop console and GUI applications

Web services

ASP.NET Web applications

Mobile applications


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To get Visual Studio.NET

You need to purchase either:

An MSDN subscription

A copy of Visual Studio.NET Academic editions are available (in or through the

bookstore ?)

Vi l St di NET


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Visual Studio.NET

Start up Visual Studio.NET

Open a new project by either: Clicking on theNew Projectbutton on the Start Page

OR

File-> New-> Project from the Menu Bar

In Visual C# Projects, create a ConsoleApplication

Implement the Main() method

Notice you now have IntelliSense

Add the Console.WriteLine line of code.

Compile using the Build menu.

Run using the Debug menu


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Your code should look like this

using System;

namespace HelloVS{//////Summary description for App.///class App{

//////The main entry point for the application.///[STAThread]static void Main(string[] args)

{System.Console.WriteLine("Hello World");

}}}

Cl E i (ti i tti )


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Class Exercise (time permitting)

Using the Visual Studio.NET write an interactive console

program to accept information from the keyboard and

then format and display the information back. It might be

a persons name and address or a variable list of favorite

pets including name and type of animal or whatever.Focus on formatting the data, looping to accept multiple

entries, testing for missing information and also testing

for an at end condition. A sample, somewhat simplified

example is in the Class Collections zip file on the web(i.e. www.PondviewSoftware.com).


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Homework Part 1

Send Me An Email

[email protected], include thefollowing:

1. Full Name, Nick Name, Student ID #

2. Home Phone / Work Phone

3. Email Address (s) [email gives me one]4. Your background in computing/programming

5. Any experience with .NET, other courses, ?

6. Your objective or goals for this course

7. Any material you have a special interest in covering?

8. Any issues or questions that you have?

9. Which additional dates you would attend classes on.
mailto:[email protected]:[email protected]


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Homework Part 2

C#.Net Programming

Homework AssignmentWeek 1

Assignment Due: November 13, 2003 5:30 PM

Write a C# NET Console Application which


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Write a C#.NET Console Application, which

performs the fol lowing:1. Accepts a first name string, a middle name string, and a last name string from

the console. The first name and last name are required. The middle name isoptional.

2. Concatenates the two or three fields together creating a full name string.

3. Truncates the full name to 20 characters if the length of the full name islonger than 20 characters.

4. Provides the capability of displaying the full name either vertically orhorizontally and forward or backward as desired.

5. Allows the full name field to be displayed in either of these four ways asmany times as desired.

6. Allows the user to go back to the top and start over, entering a new name.

7. Terminates gracefully.

Note:

There was enough information discussed in todays class to complete thisassignment. Feel free to use any additional commands, structures, orfunctions you wish.


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Dot NET Fundamentals Part2

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