using System;

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​

class circle{

     static float pi;  //these member is static because these member in common to all objects;

    int radius;

    static circle(){    //these is static construtor which can be used to intialize the static field;and it can be called before the instance construtor;and it can be called  only once

        pi=3.24F;

        Console.WriteLine("static constructor called");

    }

    public circle(int radius){

        this.radius=radius;

        Console.WriteLine("instance constructor called");

    }

    public static void printarea(){                        // these is static method which is common for all objects so we define with a static keyword.

        Console.WriteLine("area of circle will be");

    }

    public float area(){

        //float area = (int)Math.Round(3*pi*radius*radius);

        return circle.pi*this.radius*this.radius;                //we cannot access static member using this keyword so we can access by using class name.

                //Console.WriteLine("area of circle :{0}",area);

​

    }

}

public class Program

{

    public static void Main()

    {

        circle c=new circle(5);

        float area=c.area();

        Console.WriteLine("area of circle:{0}",area);

        circle c2=new circle(11);

        float area1=c2.area();

        Console.WriteLine("area of circle:{0}",area1);

        circle.printarea();    // we can access a static mwthod without creating an instance so here we can acess by using its class name.

    }

}

// if any of the instance member is staic for all the objects then we make copy of that member for all objects.means we hav e to create a separate static memory for all objects.