栈，队列 in JavaScript

// 在JavaScript里面，已经拥有push ,pop,shift,unshift的功能，但是，直接用太过简单。

 1 // 队列
 2 function Queue() {
 3     var arr = [];
 4     var size = 0;
 5 
 6     var push = function(num) {
 7         arr[size] = num;
 8         size++;
 9     };
10     var shift = function() {
11         var ret = arr[0];
12         for (var i = size-1;i>0;i--){
13             arr[i-1] = arr[i];
14         }
15         size--;
16         arr.length = size; // arr[size] = null;
17         return ret;
18     };
19     var peek = function() {
20         return arr[size-1];
21     };
22 
23     var isEmpty = function() {
24         if(size === 0) {
25             return true;
26         }
27             return false;
28     };
29 
30     return {
31         shift: shift,
32         push: push,
33         peek: peek,
34         isEmpty: isEmpty
35     };
36 };
37 var qu = new Queue();

 1 // 栈
 2 function Stock(num) {
 3     var arr = [];
 4     var size = 0;
 5 
 6     this.push = function(num) {
 7         arr[size] = num;
 8         size++;
 9     }
10     this.pop = function() {
11         var ret = arr[--size];
12         arr[size] = null;
13         return ret;
14     }
15     this.peek = function() {
16         return arr[size-1];
17     };
18 
19     this.isEmpty = function() {
20         if(size === 0) {
21             return true;
22         }
23             return false;
24     };
25     this.getSize = function() {
26         return size;
27     }
28 };
29 var st = new Stock();