testcast.java

金旭亮的java教案

class Mammal{}
class Dog extends Mammal {}
class Cat extends Mammal{}

public class TestCast
{
	public static void main(String args[])
	{
		Mammal m;
		Dog d=new Dog();
		Cat c=new Cat();
		m=d;
		//d=m;
		d=(Dog)m;
		//d=c;
		//c=(Cat)m;

	}
}