Myclass.java

abstract class Myclass {    
    abstract void calculate(double x);
}
class sub1 extends Myclass{
    void calculate(double x)
    {
        System.out.println("Square = " + (x*x));
    }
}
class sub2 extends Myclass{
    void calculate(double x)
    {
        System.out.println("Square root = " + Math.sqrt(x));
    }
}
class sub3 extends Myclass{
    void calculate(double x)
    {
        System.out.println("Cubic = " + (x*x*x));
    }
}
class Different
{
    public static void main(String args[])
    {
        Myclass ref = new sub1();
        ref.calculate(3);
        ref= new sub2();
        ref.calculate(4);
        ref = new sub3();
        ref.calculate(5);
    //     sub1  obj1 = new sub1();
    //     sub2 obj2 = new sub2();
    //     sub3 obj3 = new sub3();
    //     obj1.calculate(3);
    //     obj2.calculate(4);
    //     obj3.calculate(5);
    }
}