一、栈
    特点：后进先出（LIFO），Stack类
    function Stack() {
    var items = [];
    this.push = function(element){
    items.push(element);
    };
    this.pop = function(){
    return items.pop();
    };
    this.peek = function(){
    return items[items.length-1];
    };
    this.isEmpty = function(){
    return items.length == 0;
    };
    this.size = function(){
    return items.length;
    };
    this.clear = function(){
    items = [];
    };
    this.print = function(){
    console.log(items.toString());
    }; }

    十进制转二进制： 10转换成二进制为：1010

    二、队列 60页
    特点：先进先出（FIFO），Queue类
    function Queue() {
    var items = [];
    this.enqueue = function(element){
    items.push(element);
    };
    this.dequeue = function(){
    return items.shift();
    };
    this.front = function(){
    return items[0];
    };
    this.isEmpty = function(){
    return items.length == 0;
    };
    this.clear = function(){
    items = [];
    };
    this.size = function(){
    return items.length;
    };
    this.print = function(){
    console.log(items.toString());
    };
    }