java用数组实现栈_JAVA_编程开发_程序员俱乐部

public class Stack {
	private Object[] stack;
	//这个不需要;
	//private int top = 0; //初始化栈顶
	//这个也不需要;
	//写一个栈出来,最好是可以动态的,可以自己改变大小的,即数组的长度;
	//private int size = 0; // 初始化大小
	
	//元素个数;
	private int size;
	
	//默认长度为10;
	public Stack(){
		this(10);
	}
	
	//也可以自己设置长度,即容量;
	public Stack(int len){
		stack = new Object[len];
	}
	
	//返回元素个数;
	public int size(){
		return size;
	}
	
	//返回数组长度,即容量;
	public int capacity(){
		return stack.length;
	}
	
	//实现动态的数组;
	public void ensureCapacity(){
		if(size() == capacity()){
			Object[] newStack = new Object[size() * 3 / 2 + 1];
			System.arraycopy(stack, 0, newStack, 0, size());
			stack = newStack;
		}
	}
	
	//入栈;
	public void push(Object o){
		size++;
		ensureCapacity();
		stack[size - 1] = o;
	}
	
	/*
	public void push(Object object) {
		if (isFull()) {
			System.out.println("栈满!  入栈失败");
		}
		stack[top++] = object;
	}
	*/
	
	//判空;
	public boolean isEmpty(){
		return size == 0;
	}
	
	//出栈;
	public Object pop(){
		//首先要判空;
		if(isEmpty()){
			throw new ArrayIndexOutOfBoundsException("不能为空");
		}
		
		Object o = stack[--size];
		stack[size] = null;
		return o;
	}
	
	/*
	// 出栈
	public Object pop() {
		Object object = stack[--top];
		stack[top] = null;
		return object;
	}
	*/
	
	/*
	// 计算栈当前大小
	public int size() {
		return top;
	}

	// 判断是否是空栈
	public boolean isEmpey() {
		return top == 0;
	}

	// 判断是否栈满
	public boolean isFull() {
		return top >= size;
	}

	public Stack(int size) {
		this.size = size;
	}
	*/
	
	public static void main(String[] args) {
		Stack stack = new Stack(3);
		String[] data = new String[] { "a", "b", "c" };
		for (int i = 0; i < data.length; i++) {
				stack.push(data[i]);
				System.out.println(data[i] + "");
		}
		System.out.println("***********");
		while (!stack.isEmpty()) {
			System.out.println(stack.pop() + "");
		}
		//} 
    }
}