js之队列01


<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>队列</title>
    
    <script type="text/javascript">
    
     //开始准备实现队列
     function Queue() {
        
        this.dataStore = [];
        this.enqueue = enqueue;
        this.dequeue = dequeue;
        this.front = front;
        this.back = back;
        this.toString = toString;
        this.empty = empty;
     }
     
     //入队
     function enqueue(element) {
        this.dataStore.push(element);
     }
     //出队
     function dequeue() {
        return this.dataStore.shift();
     }
     
     //读取队首
     function front() {
        return this.dataStore[0];
     }
     
     //读取队尾
     function back() {
        return this.dataStore[this.dataStore.length-1];
     }
     
     //显示队列中所有元素
     function toString() {
        var retStr = "";
        
        for(var i = 0; i < this.dataStore.length; ++i) {
            retStr += this.dataStore[i] + "
";
        }
        
        return retStr;
     }
     
     //队列是否为空
     function empty() {
        if(dataStore.length == 0){
            return true;
        }
        else {
            return false;
        }
     }
    
    
     //测试
     
     //构造对象
     var q = new Queue();
     
     //入队
     q.enqueue("A");
     q.enqueue("B");
     q.enqueue("C");
     q.enqueue("D");
     
     //打列元素
     console.log(q.toString());
     
     //队首
     console.log("Front of queue: " + q.front());
     
     //道尾
     console.log("Back of queue: " + q.back());
     
     //出队
     q.dequeue();
     
      //队首
     console.log("Front of queue: " + q.front());
     
     //道尾
     console.log("Back of queue: " + q.back());
     
      //打列元素
     console.log(q.toString());
     
    </script>
    
</head>
<body>

</body>
</html>

//效果