数据结构03.1->Stack栈的模拟(数组)

package aa.bb.cc.demo;

import java.util.Stack;

/**
 * Stack的模拟(数组)
 * @author 州伟
 * @note 用数组模拟一个栈，注意数组是没有变化的，不会删除数组节点，主要是利用top值的变化来实现stack
 */
public class MyStack {
	//Stack底层是一个数组(当然也可以list vector等，主要看是否要线程安全？？？？)
	private long[] arr;
	private int top;	//Stack顶
	
	//默认构造方法
	public MyStack(){
		arr = new long[10];
		top = -1;
		
	}
	
	//带参数的构造方法
	public MyStack(int maxSize){
		arr = new long[maxSize];
		top = -1;
	}
	
	//添加数据???
	public void push(int value){
		/**
		 * 这样理解
		 * arr[top=top+1] = value;
		 */
		arr[++top] = value;	
	}
	
	//移除一个数据???
	public long pop(){
		/**
		 * 没有删除的过程??????
		 */
		return arr[top--];
	}
	
	//查看数据???
	public long peek(){
		return arr[top];
	}
	
	//判断是否为空
	public boolean isEmpty(){
		return top == -1;
	}
	
	//判断是否满了
	public boolean isFull(){
		return top == arr.length -1;
	}
	
	
	/**
	 * main
	 * @param args
	 */
	public static void main(String[] args) {
		MyStack ms = new MyStack(4);
		ms.push(23);
		ms.push(1);
		ms.push(90);
		ms.push(12);
		System.out.println(ms.isEmpty());
		System.out.println(ms.isFull());
		
		System.out.println(ms.peek());
		System.out.println(ms.peek());
		System.out.println();
		
		//先进后出，先出后进
		while(!ms.isEmpty()){
			System.out.println(ms.pop());
		}
		
		System.out.println(ms.isEmpty());
		System.out.println(ms.isFull());
		
		System.out.println("--------------自己模拟的stack与JDK中的Stack对比----------------");
		
		//JDK中的Stack
		Stack stack = new Stack();
		stack.push(23);
		stack.push(1);
		stack.push(90);
		stack.push(12);
		System.out.println(stack.isEmpty());
		
		System.out.println(stack.peek());
		System.out.println(stack.peek());
		System.out.println();
		
		//先进后出，先出后进
		while(!stack.isEmpty()){
			System.out.println(stack.pop());
		}
		
		System.out.println(stack.isEmpty());

	}

}