1) Write a java program that demonstrate on Interface below figure.

 class A

{

void sqcube(int n)

{

int sq=n*n;

int c=n*n*n;

System.out.println("square "+sq+ " cube "+c);

}

}

interface C

{

public void display();

}

class B extends A implements C

{

void add(int a, int b)

{

System.out.println("add= "+(a+b));

}

public void display()

{

System.out.println("this is C interface method");

}

}

class D extends B

{

void sub(int a, int b)

{

System.out.println("sub= "+(a-b));

}

}

class interfacedemo2

{

public static void main(String as[])

{

D ob=new D();

ob.display();

ob.sqcube(4);

ob.add(23,5);

ob.sub(100,50);

}

}

output:

this method from C interface

square 16 cube 64

add= 28

sub= 50