Chapter 16, Problem 12PE

Program Plan Intro

Queue as a sequence of nodes

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 element to the node.
      • Assign the null value.
      • 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 new node.
      • Set the new element to the rear end element.
      • Set the new element to the front 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.
    • Set the next element to the rear end of the queue.
    • Check whether the rear end of the queue contains null value,
      • If it is true, return null value.
    • Return the 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.
    • Execute loop till queue becomes empty,
      • Print the element removed from the queue.
    • Print new line.
    • Print the expected output.