constructor in c#

What is Class

Class is the way to realize real time entity in Object Oriented programming language. It is the user defined data type.

Syntax of Class

public class Class_Name

Note: public is an access modifier which can be anything like public,private etc.

what is Object

Object is the Runtime Entity of the Class.

Syntax of object Creation

Class_Name object_Name=new Class_Name()

What is Constructor

Constructor is the method inside the class which is used to initialize or give default value to the class member variable. It is invoked when we create new instance of the class.

Features of Constructor

It has same name as the name of the class
It is called automatically when the instance of the class created.
It doesn’t have any return type not even void

Syntax of Constructor

Public class_name(){}

For Example

In the following example we are creating a class in which declare two variable of type integer and a constructor which initialize these values with some default value.

AppCode/Class1.cs

		
		
	using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

public class Class1  //Class Creation Syntax
{
    public int x; //variable of class
    public int y;
       public Class1() //construtor(on the name of the class)
       {
        x = 2; //initializing the value
        y = 3;
       }
}

		
		
		

Default.aspx.cs

		
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        Class1 cl = new Class1();//object creation
        lblx.Text = cl.x;//calling the variable
        lbly.Text = cl.y;

    }
}

We create the instance of the class1 cl. At the time of creating the class’s object the constructor has called automatically and after that we show these class variable values in the lables which shows the following output.

		
		
		

		Figure 1