C# notes part ->1
C#.NET
C#.net has been invented by Microsoft. It is a Component Object Oriented Programming Language of C and C++ family.
It supports
Ø Cross language Integration with .net supported languages.
Ø Multiple class evaluation
Ø Multiple threading
Ø Exception handling
Ø Boxing and Unboxing Techniques
Ø Delegates
Ø Unsigned Data types
Ø Assemblies
C# is a case sensitive language.
Structure of the C#.net program:-
Public class classname
{
public static void Main()
{
// Input Output statements
}
}
Eg:- Open notepad and type below program
public class Sample
{
public static void Main()
{
System.Console.WriteLine(“Welcome to C# Programming”);
}
}
Save this notepad in D:\DFI\Consoleapp\welcome.cs
Set the c-sharp compiler(csc) path:
Copy the path where csc.exe located: C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727.
Goto MyComputer
|
Properties
|
advance Tab
|
Envijronment Variables
|
System Variables
|
Select path (edit)
|
;Paste
|
Ok
|
Ok
Open command prompt and type csc
Type below commands at command prompt
Compiling :-- D:\DFI\Consoleapp\>csc Welcome.cs
Executing :--D:\DFI\Consoleapp\>Welcome
Output:-- Welcome to C# Programming
Namespace is a collection of classes.
Collection of namespaces is an Assembly.
The root namespace should be match with the Assembly name.
Namespace n1
{
public class Sample
{
public static void Main()
{
----
----
}
}
}
Eg:--
Namespace n1
{
public class Sample
{
public static void Main()
{
System.Console.WriteLine(“Welcome to C# Programming”);
}
}
}
creating console application through Visual Studio:
StartàprogramsàMicrosoft Visual Studio 2005àVisual Studio2005àFileàNew àProject
Project Type Template
Visual C# Console Application
Name : Demo
Location: D:\DOTNET\Mid\ConsoleApp
OK
namespace Demo
{
class Program
{
static void Main(string[] args)
{
System.Console.WriteLine("Welcome");
System.Console.ReadLine();
}
}
}
press F5 key to compile and Debug.
“using” keyword is used to avoid the repetitions of namespace.The main purpose of namespace is to avoid the naming collision of classname.
Eg:
System.Console.WriteLine();
| | |
Namespace Class Method
using System;
namespace Demo
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("The DotNet Languages are\n");
Console.WriteLine("C#");
Console.WriteLine("VB");
Console.WriteLine("VC++");
Console.ReadLine();
}
}
}
Press F5 to view output.
input output statements:
Console.WriteLine() is used to display some message on the screen.
Eg: i). Console.WriteLine(“Welcome”);
ii). Console.WriteLine(string format, Object args);
Eg: int a;
a=10;
Console.WriteLine(“{0}”,a);
Console.ReadLine() is used to read the data from the keyboard as a string.
String str=Consoe.ReadLine();
Write a program to read the data and display it.
using System;
namespace ReadWrite
{
class Program
{
static void Main(string[] args)
{
int a;
Console.WriteLine("Enter the value of a");
a = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("The value of a is " + a);
Console.ReadLine();
}
}
}
Accept two numbers and display them.
using System;
namespace ReadWriteAB
{
class Program
{
static void Main(string[] args)
{
int a,b;
Console.WriteLine("Enter the values of a and b");
a = Convert.ToInt32(Console.ReadLine());
b = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("The value of A = {0} and B = {1} " , a,b);
Console.ReadLine();
}
}
}
NOTE: here the Convert is a class which is required to convert one datatype to another datatype.
Boxing is a concept of storing the value type as a reference type.
Unboxing is a concept of storing the reference type as a value type.
Operators:
Arithmetic +, -, *, %, /.
Comparison <, >, <=, >=, !, ==
Logical &&, ||, !=
Concatenation +
using System;
namespace OperatoreEx
{
class Program
{
static void Main(string[] args)
{
int a, b;
Console.WriteLine("Enter the values of a and b");
a = Convert.ToInt32(Console.ReadLine());
b = Convert.ToInt32(Console.ReadLine());
Console.WriteLine(" A+B={0}, A-B={1}, A*B={2}, A%B={3}, A/B={4} ",a+b,a-b,a*b,a%b,a/b);
Console.ReadLine();
}
}
}
Conditional Statements
if else
switch-case
loops
while
do-while
for
foreach
foreach(datatype variable in list)
{ |
………… array list
}
Eg:
using System;
namespace ForeachEg
{
class Program
{
static void Main(string[] args)
{
int[] Score = { 100, 20, 30 };
foreach (int i in Score)
{
Console.WriteLine(i+"\t");
}
Console.ReadLine();
}
}
}
ARRAYS
Array is a collection of homogeneous elements which will be stored in a consecutive memory location.
Eg: A={10,20,30,40};
A[0]=10
A[1]=20
A
10 | 20 | 30 | 40 |
0 1 2 3 àindex
Syntax: Datatype [] Arrayname;
Eg: int [] Score;
string [] StuName;
Array Types
1. Single Dimension array
2. Multi Dimension array
3. Jagged array
Note: array is Base class for all the properties and methods.
Array Properties: Length, Rank
Array Methods: GetLength(), Sort(), Copy().
1. Single Dimension array:
Syntax:
a).datatype [] arrayname;
Arrayname=new datatype[size];
Eg: int [] Score;
Score =new int[5];
b).datatype [] arrayname =new datatype[size];
Eg: int [] Score=new int[5];
c).datatype[] arrayname={collection of elements};
Eg: int [] Score={100,20,30,40};
using System;
namespace SingleDimArrayEx
{
class Program
{
static void Main(string[] args)
{
int[] Score = new int[5];
Console.WriteLine("enter the elements");
for (int i = 0; i < Score.Length; i++)
{
Score[i] = Convert.ToInt32(Console.ReadLine());
}
Console.WriteLine("the values of the array are");
for (int i = 0; i < Score.Length; i++)
{
Console.Write(Score[i] + "\t");
}
Console.WriteLine();
Array.Sort(Score);
Console.WriteLine("your sorted array is ");
for (int i = 0; i < Score.Length; i++)
{
Console.Write(Score[i] + "\t");
}
Console.ReadLine();
}
}
}
Multi Dimension Array:
Syntax:
Datatype [,] arrayname;
Datatype [,] arrayname=new datatype[row size,column size];
eg: int[,] Test =new int[2,3];
using System;
namespace multiarrayapp
{
class Program
{
static void Main(string[] args)
{
int[,] MulScore= new int[2, 2];
Console.WriteLine("enter the elements into an array");
for (int i = 0; i < MulScore.GetLength(0); i++)
{
for (int j = 0; j < MulScore.GetLength(1); j++)
{
MulScore[i, j] = Convert.ToInt32(Console.ReadLine());
}
}
Console.WriteLine();
Console.WriteLine("the array values are");
for (int i = 0; i < MulScore.GetLength(0); i++)
{
for (int j = 0; j < MulScore.GetLength(1); j++)
{
Console.Write(MulScore[i, j] + "\t");
}
Console.WriteLine();
}
Console.ReadLine();
}
}
}
Jagged Array:
Arrays of an array is called as a jagged array where rows are fixed and columns are not fixed.
Eg:
10 | 20 | |
30 | 40 | 50 |
60 | ||
70 | 80 | 90 |
100 | ||
Syntax:
Datatype [][] jagarrayname = new datatype [rowsize][];
int [][] JagScore = new int[5][];
JagScore[0]=new int[2] {10,20};
JagScore[1]=new int[3] {30,40,50};
JagScore[2]=new int[1] {60};
JagScore[3]=new int[3] {70,80,90};
JagScore[4]=new int[1] {100};
using System;
namespace jarray
{
class Program
{
static void Main(string[] args)
{
int[][] JagArray = new int[5][];
JagArray[0] = new int[2] { 10, 20 };
JagArray[1] = new int[3] { 30, 40, 50 };
JagArray[2] = new int[1] { 60 };
JagArray[3] = new int[3] { 70, 80, 90 };
JagArray[4] = new int[1] { 100 };
Console.WriteLine("\n\n\n your jagged array is \n");
for (int i = 0; i < JagArray.GetLength(0); i++)
{
for (int j = 0; j < JagArray[i].Length; j++)
{
Console.Write(JagArray[i][j] + "\t");
}
Console.WriteLine();
}
Console.ReadLine();
}
}
}
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