Question

In: Computer Science

Problem 3 Prototype object doubleQ A doubleQ object has 2 instance variables: firstQ and secondQ arrays...

Problem 3

Prototype object doubleQ

A doubleQ object has 2 instance variables: firstQ and secondQ

arrays that together implement a queue

enqueue() instance method adds its argument to the end of this.secondQ

dequeue() instance method removes and returns the element at the front of this.firstQ

transfer() instance method removes the element from the front of this.secondQ, adds it to the end of this.firstQ

If this.secondQ is empty, does nothing

Test code is included in the file

Download this file (with fragments missing)

Hint: Use the push() and shift()

Listing

<html>

<head>

<title>Assignment 3, Problem 3</title>

function doubleQ( q1, q2 )

{

this.firstQ = q1 || [];

this.secondQ = q2 || [];

this.enqueue = function( item )

{ }; // Code missing

this.dequeue = function()

{ }; // Code missing

this.toString = function()

{ return "[" + this.firstQ + "] ["

+ this.secondQ + "]"; };

}

function doubleQ_transfer()

{

// Code missing

}

doubleQ.prototype.transfer = doubleQ_transfer;

var dQ = new doubleQ( [1, 2], [3, 4] );

document.write( "dQ: " + dQ + "" );

dQ.transfer()

document.write( "After transfer: " + dQ + "" );

document.write( "Value dequeued: " + dQ.dequeue() + "" );

document.write( "After dequeue: " + dQ + "" );

dQ.enqueue(5);

document.write( "After enqueuing 5: " + dQ + "" );

</script>

</head>

<body>

</body>

</html>

Output

dQ: [1,2] [3,4]

After transfer: [1,2,3] [4]

Value dequeued: 1

After dequeue: [2,3] [4]

After enqueuing 5: [2,3] [4,5]

Solutions

Expert Solution

Below is the solution with output screenshot

Code :

<html>
   <head>
      <title>Assignment 3, Problem 3</title>
      <script type="text/Javascript">
        function doubleQ(q1, q2) {
            this.firstQ = q1 || [];
            this.secondQ = q2 || [];
            this.enqueue = function(item) {
                this.secondQ.push(item);
            }; // Code missing
            this.dequeue = function() {
                return this.firstQ.shift();
            }; // Code missing
            this.toString = function() {
                return "[" + this.firstQ + "] [" + this.secondQ + "]";
            };
        }

        function doubleQ_transfer() {
            // Code missing
            this.firstQ.push(this.secondQ.shift());
        }
        doubleQ.prototype.transfer = doubleQ_transfer;
        var dQ = new doubleQ([1, 2], [3, 4]);
        document.write("<p>dQ: " + dQ + "</p>");
        dQ.transfer()
        document.write("<p>After transfer: " + dQ + "</p>");
        document.write("<p>Value dequeued: " + dQ.dequeue() + "</p>");
        document.write("<p>After dequeue: " + dQ + "</p>");
        dQ.enqueue(5);
        document.write("<p>After enqueuing 5: " + dQ + "</p>");
         
      </script>
   </head>
   <body>
   </body>
</html>

Output :

venereology answered 2 months ago

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