using System;

​

class Circle

{

    static float _PI;

    int _Radius;

    static Circle()

    {

        Circle._PI = 3.141F;

    }

    public Circle(int Radius){

     this._Radius = Radius;

    }

    public float CalculateArea()

    {

    return Circle._PI * this._Radius * this._Radius;

    }

}

​

​

​

​

public class Program

{

    public static void Main()

    {

        Circle C1 = new Circle(5);

        float Area = C1.CalculateArea();

        Console.WriteLine("Area = {0}" , Area);

        Circle C2 = new Circle(10);

        float Area1 = C2.CalculateArea();

        Console.WriteLine("Area = {0}" , Area1);

    }

}