/**
 * [Queue]
 * @param {[Int]} size [队列大小]
 */
function Queue(size) {
  var list = [];
  //向队列中添加数据
  this.push = function(data) {
    if (data==null) {
      return false;
    }
    //如果传递了size参数就设置了队列的大小
    if (size != null && !isNaN(size)) {
      if (list.length == size) {
        this.pop();
      }
    }
    list.unshift(data);
    return true;
  }
  //从队列中取出数据
  this.pop = function() {
    return list.pop();
  }
  //返回队列的大小
  this.size = function() {
    return list.length;
  }
  //返回队列的内容
  this.quere = function() {
    return list;
  }
}
//初始化没有参数的队列
var queue = new Queue();
for (var i = 1; i <= 5; i++) {
  queue.push(i);
}
console.log(queue.quere());
console.log(queue.pop());  //从队列中取出一个
console.log(queue.quere());
var queue = new Queue(3);
for (var i = 1; i <= 5; i++) {
  queue.push(i);
}
console.log(queue.quere());
console.log(queue.pop());
console.log(queue.quere());

[ 5, 4, 3, 2, 1 ]
1
[ 5, 4, 3, 2 ][ 5, 4, 3 ]
3
[ 5, 4 ]