代码块，继承，多态，接口等基本概念

思维导图

看程序写结果1

	    class Fu{
		public int num = 10;
		public Fu(){
			System.out.println("fu");
		}
	}
	class Zi extends Fu{
		public int num = 20;
		public Zi(){
			System.out.println("zi");
		}
		public void show(){
			int num = 30;
			System.out.println(num);//30
			System.out.println(this.num);//20
			System.out.println(super.num);//10
		}
	}
	class Test {
		public static void main(String[] args) {
			Zi z = new Zi();
			z.show();
		}
	}

结果：fu
zi
30
20
10

看程序写结果2

          class A {
		public void show() {
			show2();
		}
		public void show2() {
			System.out.println("我");
		}
	}
	class B extends A {
		public void show2() {
			System.out.println("爱");
		}
	}
	class C extends B {
		public void show() {
			super.show();
		}
		public void show2() {
			System.out.println("你");
		}
	}
	public class DuoTaiTest4 {
		public static void main(String[] args) {
			A a = new B();
			a.show();
			
			B b = new C();
			b.show();
		}
	}

答：爱
你