在Cycle中添加wheels()方法，它将返回轮子的数量。修改ride()方法，让它调用wheels()方法，并验证多态起作用了
package com.experice;
public class Cycle {
int num;
public void ride(int n) {
//System.out.println("Cycle.ride()");
System.out.println(wheels(n));
}
public int wheels(int n) {
return n;
}
}
package com.experice;
public class Unicycle extends Cycle{
static int num = 1;
public void ride(int n) {
//System.out.println("Unicycle.ride() " + n);
System.out.println(wheels(n));
}
}
package com.experice;
public class Bicycle extends Cycle{
static int num = 2;
public void ride(int n) {
//System.out.println("Bicycle.ride() " + n);
System.out.println(wheels(n));
}
}
package com.experice;
public class Tricycle extends Cycle{
static int num = 3;
public void ride(int n) {
//System.out.println("Tricycle.ride() " + n);
System.out.println(wheels(n));
}
}
package com.experice;
public class CycleTest {
/*public static void tune(Cycle c) {
//b.ride(Node.BICYCLE);
c.ride(u.num);
}*/
/*public static void tune(Unicycle b) {
b.ride(Node.UNICYCLE);
}
public static void tune(Tricycle b) {
b.ride(Node.TRICYCLE);
}*/
public static void main(String[] args) {
/*Unicycle u = new Unicycle();
Bicycle b = new Bicycle();
Tricycle t = new Tricycle();
tune(u);
tune(b);
tune(t);*/
Cycle c = new Unicycle();
Cycle c2 = new Bicycle();
Cycle c3 = new Tricycle();
/*System.out.println(Unicycle.num);
System.out.println(Bicycle.num);
System.out.println(Tricycle.num);*/
c.ride(Unicycle.num);
c2.ride(Bicycle.num);
c3.ride(Tricycle.num);
}
}
输出结果:
1
2
3