interface calculation
    {
        void calculate(int Num);
    }
    class display implements calculation
    {
        int p;
        public void calculate(int Num)
        {
            p = Num * Num;            
        }
    }
    
    public class interfaces_Example
    {
        public static void main(String args[])
        {
            display object = new display();
            object.p = 0;      
            object.calculate(4);
            System.out.print(object.p);
        }
    }