//PROGRAM 8-7
interface IInduk {
  double tambah(double a, double b);
  double kurang(double a, double b);
}

interface ITurunan extends IInduk {
  double kali(double a, double b);
  double bagi(double a, double b);
}

class Aritmetika implements ITurunan {	
  private double x;
  private double y;
  
  Aritmetika(double x, double y) {
    this.x = x;
    this.y = y;
  }
  
  public double tambah(double a, double b) {
    return (a + b);
  }
  
  public double kurang(double a, double b) {
    return (a - b);
  }
  
  public double kali(double a, double b) {
    return (a * b);
  }
  
  public double bagi(double a, double b) {
    return (a / b);
  }
  
  public void cetakHasil() {
    System.out.println("x = " + x);
    System.out.println("y = " + y);
    System.out.println();
    System.out.println("x + y = " + tambah(x, y));
    System.out.println("x - y = " + kurang(x, y));
    System.out.println("x * y = " + kali(x, y));
    System.out.println("x / y = " + bagi(x, y));
  }
}

class DemoInterfaceTurunan {  
  public static void main(String[] args) {
    // membuat objek Aritmetika dengan x=10.0 dan y=2.5
    Aritmetika obj = new Aritmetika(10.0, 2.5);  	
    obj.cetakHasil();  	
  }	
}