Chapter 16, Problem 14PE

Program Plan Intro

A method “lastToFirst()”

Program plan:

• In a file “LinkedListQueue.java”, import necessary package, and create a class “LinkedListQueue”,
  • Declare the necessary “Node” object variables.
  • Define the constructor to create the empty queue.
  • Define the method “empty()” to check whether the queue is empty.
  • Define the method “add()” to insert the element at rear end of the queue,
    • Check whether the rear end of the queue contains null value,
      • If it is true, create an object for “Node”.
      • Assign the new element to the node.
      • Assign the null value the next node.
      • Assign the new node value to the rear element.
      • Assign the new node value to the front end element.
    • Otherwise,
      • If it is true, create an object for “Node”.
      • Assign the element to the node.
      • Assign the null value to the node next to the new node.
      • Set the new element to the rear end element.
      • Set the new element to the rear end element.
  • Define the method “remove()” to remove the element from front end of the queue,
    • Check whether the front end of the queue contains null value,
      • If it is true, return null value.
    • Initialize the object.
    • Assign the element next to front element to the front end of the queue.
    • Check whether the rear end of the queue contains null value,
      • If it is true, assign the null value to rear end of the queue.
    • Return the element.
  • Define the method “lastToFirst ()” to move the tail of the queue to the head of the queue,
    • Check whether the rear end and front end element is not same.
      • If it is true, initialize the “Node” object.
      • Set the head of the queue to the node next to rear of the queue.
      • Assign the rear element to the front element.
      • Execute till the value becomes null,
        • Check the condition,
        • • If it is true, set the null value to the element next to check element.
          • Set the check element to the rear element.
        • Set the next element to the check element.
  • Create a class “Node”,
    • Declare the object for “Object” and “Node”.
• In a file “QueueTest.java”, create a class “QueueTest”,
  • Define the “main()” method.
    • Create “LinkedListQueue” object.
    • Add the element “Jerry” to the rear end of the queue.
    • Add the element “Daniel” to the rear end of the queue.
    • Add the element “John” to the rear end of the queue.
    • Call the method “lastToFirst()”.
    • Execute loop till queue becomes empty,
      • Print the element removed from the queue.
    • Print new line.
    • Print the expected output.