Java，主函数访问这些方法并执行数学运算

public class Ex5 {
    public static void main(String[] args) {
        MulDiv m1 = new MulDiv();
        System.out.println("num1="+m1.num1);
        System.out.println("num2="+m1.num2);
        System.out.println("加法结果:"+(m1.num1+m1.num2));
        System.out.println("乘法结果:"+m1.multiply());
        System.out.println("除法结果:"+m1.divide());
    }
}
class AddSub{
    int num1,num2;
    public AddSub(){
        num1 = 100;
        num2 = 50;
    }

}
class MulDiv extends AddSub{
    public  int multiply(){
        return this.num1*this.num2;
    }
    public  int divide(){
        return this.num1/this.num2;
    }
}

运行结果:
num1=100
num2=50
加法结果:150
乘法结果:5000
除法结果:2

class AddSub{
        private int num1;
        private int num2;

        public AddSub(){
            num1=100;
            num2=50;
        }
        public int add(){
            return num1 + num2;
        }
        public int subtract(){
            return num1 - num2;
        }
    }
    class MulDiv extends AddSub {
        private int num1;
        private int num2;

        public MulDiv(){
            num1=super.num1;
            num2=super.num2;
        }
        public int multiply(){
            return num1 * num2;
        }
        public int divide(){
            return num1 / num2;
        }
    }

    class ex5{
        public static void main(String args[]){
            MulDiv m1 = new MulDiv();
            System.out.println("num1=" + m1.num1);
            System.out.println("num2=" + m1.num2);
            System.out.println("num1 + num2 = " + m1.add());
            System.out.println("num1 - num2 = " + m1.subtract());
            System.out.println("num1 * num2 = " + m1.multiply());
            System.out.println("num1 / num2 = " + m1.divide());
        }
    }