test8.5

在Cycle修改了构造函数，并增加一个wheels()函数，然后Unicycle Bicycle Triangle cycle的构造函数全部随之修改，最后根据前面的修改变化ride()就可以出来题目要求的效果

class Cycle

{private int n;
Cycle(int i){n=i;System.out.println("Cycle constructor");}
public int wheels(){return n;}}
class Unicycle extends Cycle{
Unicycle(int i){super(i);System.out.println("Unicycle constructor");}
}
class Bicycle extends Cycle{
Bicycle(int i){super(i);System.out.println("Bicycle constructor");}
}
class Tricycle extends Cycle{
Tricycle(int i){super(i);System.out.println("Tricycle constructor");}
}
public class Test5 {
public void ride(Cycle c){System.out.println("Wheels numbers= "+c.wheels());}
public static void main(String[] args) {
Test5 t=new Test5();
t.ride(new Unicycle(1));
//t.ride(new Bicycle(2));
//t.ride(new Tricycle(3));
}
}