js實現棧

棧是一種先進后出的特殊線性表結構，存儲上分鏈式存儲和順序存儲兩種方式

鏈式存儲：

function LinkedStack() {
    let Node = function (ele) {
        this.ele = ele;
        this.next = null;
    }

    let length = 0,
        top; //棧頂指針

    //壓棧操作
    this.push = function (ele) {
        let node = new Node(ele);
        top ? node.next = top : top = node;
        top = node;
        length++;
        return true;
    }

    //退棧操作
    this.pop = function () {
        let current = top;

        if (top) {
            top = current.next;
            current.next = null;
            length--;
            return current;
        } else {
            return 'null stack';
        }

    }

    this.top = function () {
        return top;
    }
    this.size = function () {
        return length;
    }
    //toString 從棧頂到棧底
    this.toString = function () {
        let string = '';
        current = top;
        while (current) {
            string += current.ele + ' ';
            current = current.next;
        }
        return string;
    }
    this.clear = function () {
        top = null;
        length = 0;
        return true;
    }
}

//使用
let myStack = new LinkedStack();
myStack.push('1')
myStack.push('2')
myStack.push('3')
myStack.push('4')
console.log(myStack.toString()) // 4 3 2 1
myStack.pop()
console.log(myStack.toString()) // 3 2 1
myStack.pop()
myStack.pop()
console.log(myStack.pop()) // Node { ele: '1', next: null }
console.log(myStack.pop()) // null stack

 

順序存儲：用js內置對象Array實現

function ArrayStack(){  
    var arr = [];  
        //壓棧操作  
    this.push = function(element){  
        arr.push(element);  
    }  
        //退棧操作  
    this.pop = function(){  
        return arr.pop();  
    }  
        //獲取棧頂元素  
    this.top = function(){  
        return arr[arr.length-1];  
    }  
        //獲取棧長  
    this.size = function(){  
        return arr.length;  
    }  
        //清空棧  
    this.clear = function(){  
        arr = [];  
        return true;  
    }  
  
    this.toString = function(){  
        return arr.toString();  
    }  
}