Chapter 16, Problem 13PP

Program Plan Intro

Double-ended queue (deque) as a circular array

Program plan:

• In a file “CircularArrDeque.java”, import necessary package, and create a class “CircularArrDeque”,
  • Declare the necessary array of type “Object”.
  • Declare the necessary 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,
    • Call the method “growBufferIfNecessary()”.
    • Increment the size.
    • Assign the new element to the rear of the queue.
    • Update the rear value.
  • Define the method “modDecrement()”,
    • Check whether the passed value is “0”,
      • If it is true, subtract “1” from the buffer length and set to the variable.
        • Otherwise, subtract “1” from the value.
        • Return the value.
  • Define the method “addFirst()”,
    • Check whether the size is greater than “0”,
      • If it is true, call the method “growBufferIfNecessary()”.
        • Increment the size by “1”.
        • Assign the value returned from the method “modDecrement()” to the front of the queue.
        • Assign the new element to the buffer’s head.
      • Otherwise,
        • Decrement the size.
        • Assign the new element to the front o the queue.
        • Set the rear of the queue as “1”.
  • Define the method “addLast()”,
    • Call the method “add()”.
  • Define the method “remove()” to remove the element from front end of the queue,
    • Check whether the current size is “0”,
      • Throw an exception.
        • • Declare and initialize the object.
          • Update the front value.
          • Decrement the size.
          • Return the object properties.
  • Define the method “removeFirst()” that returns the value returned from the method “remove()”.
  • Define the method “removeLast()”,
    • Check whether the size is greater than “0”,
      • If it is true, throws an exception “NoSuchElementException”.
        • • Assign the value to the rear of the queue.
          • Assign the tail value to the object.
          • Decrement the size.
          • Return the object.
  • Define the method “size()” that returns the current size of the queue.
  • Define the method “get()”,
    • Compute the value.
    • Return the value in the buffer.
  • Define the method “growBufferIfNecessary()”,
    • Check the condition,
      • If it is true, create an object for “Object”.
      • Create a loop,
        • Fill the object array.
      • Assign the new buffer.
      • Set the front of the queue to “0”.
      • Set the value of the rear of the queue.
• In a file “QueueTeste.java”, create a class “QueueTeste”,
  • Define the “main()” method.
    • Create “CircularArrDeque” object.
    • Add the element “John” to the first of the queue.
    • Add the element “Jerry” to the first of the queue.
    • Call the method “printAll()”.
    • Print the expected result.
    • Remove the name from the front of the deque.
    • Call the method “printAll()”.
    • Print the expected result.
    • Add the element “David” to the rear of the queue.
    • Add the element “Hassan” to the rear of the queue.
    • Add the element “Sujith” to the rear of the queue.
    • Add the element “Mithran” to the rear of the queue.
    • Call the method “printAll()”.
    • Print the expected result.
    • Remove the element from the rear of the queue.
    • Remove the element from the rear of the queue.
    • Print the expected result.
    • Print the expected result.
    • Call the method “printAll()”
    • Print the expected result.
    • Remove the element from the first of the deque.
    • Call the method “printAll()”.
    • Print the expected result.
    • Add the element “Jennie” to the front of the queue.
    • Call the method “printAll()”.
    • Print the expected result.