test8.1

题目的意思是构造一个函数ride(Cycle c)但是在使用ride()的是偶给它的参数c是Unicycle Bicycle 或者Tricycle而不是直接的Cycle，此时的参数可以完成向上转换，即编程Cycle对象，根据输出结果中出现的Cycle()构造函数知道确实出现了向上转型

class Cycle

{Cycle(){System.out.println("Cycle constructor");}}

class Unicycle extends Cycle{
Unicycle(){System.out.println("Unicycle constructor");}

}

class Bicycle extends Cycle{
Bicycle(){System.out.println("Bicycle constructor");}

}

class Tricycle extends Cycle{
Tricycle(){System.out.println("Tricycle constructor");}

}

public class Test1 {
public void ride(Cycle c){System.out.println("Test1.ride()");}
public static void main(String[] args) {
Test1 t=new Test1();
t.ride(new Unicycle());
t.ride(new Bicycle());
t.ride(new Tricycle());
}

}