Queue

[lskaiser]

I am requesting to complete a queue.

[brendanpettis]

Sounds good!

[lskaiser]

/* Queue Laura Kaiser

Queue: A queue is a data structure that temporarily holds items in a first-in-first-out (FIFO) sequence.

*/

class Queue {

//This builds the container for the objects
constructor()
{
    this.data = []; 
}

//Adds a new element to the back of the queue using the push method.
enqueue(element)
{
    this.data.push(element);
}

//Removes the element from the front of the queue using the shift method.
//by removing the first item in the array
dequeue()
{
    //First checks to see if the queue is empty.
    if(this.isEmpty()){
        return "No elements in Queue";
    }
    else{  
        return this.data.shift();
    }            
}

//Returns the first element in the queue
first()
{
    //Demonstrates a shortcut to writing "if-else" statement
    if (this.isEmpty())
        return "No elements in Queue";
    return this.data[0];      
} 

//Returns the last element in the queue by
//calculating the length of the array and subtracting by 1
last()
{
    if (this.isEmpty())
        return "No elements in Queue";
    return this.data[this.data.length - 1];        
}

print()
{
    var qString = "";
    if (this.isEmpty()){
        return "No elements in Queue";
    }
    else{
        for (var i = 0; i < this.data.length; i++)
            qString += this.data[i] + " ";
        return qString;
    }   
}

//Will return a boolean. The boolean will be true
//if the queue's length = 0
isEmpty()
{
    return this.data.length == 0;
}

}

/
----TEST CLASS---- /

var q = new Queue();

console.log(q.print()); //Expected Output: Receive empty queue error message

q.enqueue(10); q.enqueue(15); q.enqueue(30); console.log("The queue: "); console.log(q.print()); //Expected Output: 10 15 30

console.log("The first item: " + q.first()); //Expected Output: 10

console.log("The last item: " + q.last()); //Expected Output: 30

q.dequeue(); console.log("The queue after one dequeue: "); console.log(q.print()); //Expected Output: 15 30