queue.java

清华大学第二版

abstract class ObjectStorage{
	int objectnum=0;
	Object storage[] = new Object[100];

	abstract void put(Object o);	//注意: 没有大括弧("{}")
	abstract Object get();
}

class Stack extends ObjectStorage{
	private int point=0;

	public void put(Object o){
		storage[point++]=o;
		objectnum++;
	}
	public Object get(){
		objectnum--;
		return storage[--point];
	}
}

class Queue extends ObjectStorage{
	private int top=0;
	private int bottom=0;

	public void put(Object o){
		storage[top++]=o;
		objectnum++;
	}
	public Object get(){
		objectnum--;
		return storage[bottom++];
	}
}