GitHub: https://github.com/BadWaka/data-structure-algorithm/blob/master/stack/stack.html

    // 棧

    var Stack = function (size) {

        this.stack = new Array(size);   // 新建內存空間
        this.size = size;   // 棧容量
        this.top = 0;   // 棧頂

        var that = this;

        // 判斷棧是否為空
        this.isStackEmpty = function () {
            return that.top === 0;
        };

        // 判斷棧是否為滿
        this.isStackFull = function () {
            return that.top === that.size;
        };

        // 清空一個棧
        this.clearStack = function () {
            that.top = 0;
            // that.stack.splice(0, that.stack.length); // 不是必要的，因為即使棧里有值也沒有關系，只要棧頂為0了，之前的值就再也取不到了
        };

        // 獲得棧的元素個數
        this.getStackLength = function () {
            return that.top;    // 棧頂的值即可以表示棧元素的多少
        };

        // 入棧
        this.push = function (element) {
            if (that.isStackFull()) {
                console.log('棧已滿，入棧失敗 element = ' + element);
                return false;
            }
            that.stack[that.top] = element;
            that.top++;
            return true;
        };

        // 出棧
        this.pop = function () {
            if (that.isStackEmpty()) {
                console.log('空棧，出棧失敗');
                return false;
            }
            // 這里要注意，棧頂指向的是一個空的地方，用來放元素的；所以取得時候先top--，再取值
            that.top--;
            var element = that.stack[that.top];
            console.log('出棧成功 element = ' + element);
            return element;
        };

        /**
         * 遍歷棧
         *
         * @param isFromTop    是否從棧頂開始
         * @param handler   處理函數
         */
        this.traverseStack = function (isFromTop, handler) {
            var stackStr = '';
            var i;
            if (isFromTop) {
                for (i = that.top - 1; i >= 0; i--) {
                    stackStr += that.stack[i] + ' ';
                    if (handler) {
                        handler(that.stack[i]);
                    }
                }
            } else {
                for (i = 0; i < that.top; i++) {
                    stackStr += that.stack[i] + ' ';
                    if (handler) {
                        handler(that.stack[i]);
                    }
                }
            }
            console.log('棧內所有元素為 stackStr = ' + stackStr);
        };
    };

    // 測試case

    var ins = new Stack(5);

    ins.push('h');
    ins.push('e');
    ins.push('l');
    ins.push('l');
    ins.push('o');

    ins.pop();

    //    ins.clearStack();

    console.log('棧是否為空 = ' + ins.isStackEmpty());
    console.log('棧是否為滿 = ' + ins.isStackFull());
    console.log('當前棧長度 = ' + ins.getStackLength());
    ins.traverseStack();