using System;

    public delegate double  calcul(double r);

public class Program

{ static double Arie(double r)

{ return System.Math.PI * r*r; 

}

 static double Lungime(double r)

 { return 2*r* System.Math.PI ;

 }

​

    public static void Main()

    { calcul a=new calcul(Arie);

     Console.WriteLine("{0:#.##}",a(2));

     calcul b=new calcul(Lungime);

     Console.WriteLine("{0:#.##}",b(2));

    }

}