使用javaScript實現一個隊列

1.隊列是遵循先進先出（FIFO)原則的一組有序的項，隊列在尾部添加元素，並從頂部移除元素，最新添加的元素必須排在隊列的末尾。生活中常見的例子如排隊等。

2.創建一個隊列類

class Queue{
    constructor(){
        this.count = 0;//記錄隊列的數量
        this.lowestCount = 0;//記錄當前隊列頭部的位置
        this.items = [];//用來存儲元素。
    }
}

3.添加元素

  enqueue(element){
        this.items[this.count] = element;
        this.count++;
    }

4.刪除元素（只刪除隊列頭部）

    dequeue(){
        if(this.isEmpty()){
            return 'queue is null';
        }
        let resulte = this.items[this.lowestCount];
        delete  this.items[this.lowestCount];
        this.lowestCount++;
        return resulte;
    }

5.查看隊列頭部元素

    peek(){
        return this.items[this.lowestCount];
    }

6.判斷隊列是否為空

    isEmpty(){
        return this.count - this.lowestCount === 0;
    }

7.清除隊列的元素

    clear(){
        this.count = 0;
        this.lowestCount = 0;
        this.items = [];
    }

8.查看隊列的長度

 size(){
        return this.count - this.lowestCount;
    }

9.查看隊列的所有內容

  toString(){
        if(this.isEmpty())return "queue is null";
        let objString = this.items[this.lowestCount];
        for(let i = this.lowestCount+1; i < this.count;i++){
            objString = `${objString},${this.items[i]}`;
        }
        return objString;
    }

10.完整代碼

class Queue{
    constructor(){
        this.count = 0;//記錄隊列的數量
        this.lowestCount = 0;//記錄當前隊列頂部的位置
        this.items = [];//用來存儲元素。
    }
    enqueue(element){
        this.items[this.count] = element;
        this.count++;
    }
    dequeue(){
        if(this.isEmpty()){
            return 'queue is null';
        }
        let resulte = this.items[this.lowestCount];
        delete  this.items[this.lowestCount];
        this.lowestCount++;
        return resulte;
    }
    peek(){
        return this.items[this.lowestCount];
    }
    isEmpty(){
        return this.count - this.lowestCount === 0;
    }
    size(){
        return this.count - this.lowestCount;
    }
    clear(){
        this.count = 0;
        this.lowestCount = 0;
        this.items = [];
    }
    toString(){
        if(this.isEmpty())return "queue is null";
        let objString = this.items[this.lowestCount];
        for(let i = this.lowestCount+1; i < this.count;i++){
            objString = `${objString},${this.items[i]}`;
        }
        return objString;
    }
}

11.運行結果