56 面向对象this和super的区别和应用

 1 class Demo1_Extends{
 2     public static void main(String[] args) {
 3         Dog d = new Dog();
 4         d.print();
 5     }
 6 }
 7 
 8 class Animals{
 9      int num1 = 10;
10      int num2 = 20;
11 }
12 
13 class Dog extends Animals{
14     int num2 = 30;
15     
16     public void print(){
17         System.out.println(this.num2);
18         System.out.println(this.num1);
19         System.out.println(super.num2);
20     }
21 
22 }