Chapter 16, Problem 3PE

Program Plan Intro

Faulty version of a method “hasNext()”

Program plan:

• In a file “ListIterator.java”, create an interface “ListIterator”,
  • Declare the method “next()” that moves the iterator past the next element.
  • Declare the method “hasNext()” that check if there is an element after the iterator position.
  • Declare the method “add()”  that adds an element before the position of the iterator and moves the iterator past the added element.
  • Declare the method “remove()” that removes the last traversed element.
  • Declare the method “set()” to set the last traversed element to a previous value.
• In a file “BadLinkedList.java”, import the package and create a class “BadLinkedList”,
  • Declare the object variable.
  • Define the constructor to create an empty linked list.
  • Define the method “reverse()”  that reverses the elements in the linked list.
  • Define the method “getFirst()” that returns the first element in the linked list.
  • Define the method “removeFirst()” to remove the first element in the linked list.
  • Define the method “addFirst()” that adds an element to the front of the linked list,
    • Create new node.
    • Assign new node to the first position.
    • Assign the value to the new node.
    • Assign the first element to the next.
      • Define the method “listIterator()” of type “ListIterator”, that returns an iterator for iterating through the list.
      • Create a class “Node”,
        • Declare the object variable for “Object”, and “Node”.
      • Create a class “LinkedListIterator”,
        • Declare the necessary object variables.
        • Define the constructor to create an iterator that points to the front of the linked list.
        • Define the method “next()”,
          • If there is no next element then throws an exception.
          • Assign the position to the front of the linked list.
          • Check if position is null, set the first element to the position.
          • Otherwise, set the next position to the current position.
          • Returns the value.
        • Define the method “hasNext()” that checks whether there is next element.
          • Returns true, if the position is not null.
        • Define the method “add()”,
          • If position is null, call the method “addFirst()”.
            • Set the first to the position.
          • Otherwise, create a new node.
            • Assign the element to the new node.
            • Set the next position to the next pointer of the new node.
            • Set the new node value to the next position.
            • Set the new node as the position.
          • Set the position to the previous value.
        • Define the method “remove()”,
          • Check if position is same as previous,
            • If it is true, throws an exception.
              • If position is same as the first, calls the method “removeFirst()”.
              • Otherwise, set the next position to the previous position.
              • Set the previous to the positions.
              • Assign previous to the position.
        • Define the method “set()”,
          • If position is null, throws an exception.
          • Set the value to the position.

• In a file “LinkedList.java”, import the package and create a class “LinkedList”,
  • Declare the object variable.
  • Define the constructor to create an empty linked list.
  • Define the method “reverse()” that reverses the linked list elements.
  • Define the method “getFirst()” that returns the first element in the linked list.
  • Define the method “removeFirst()” to remove the first element in the linked list.
  • Define the method “addFirst()” that adds an element to the front of the linked list,
    • Create a new node.
    • Assign the value to the new node.
    • Assign the first element to the next pointer of new node.
    • Assign new node to the first position.
      • Define the method “listIterator()” of type “ListIterator”, that returns an iterator for iterating through the list.
      • Create a class “Node”,
        • Declare the object variable for “Object”, and “Node”.
      • Create a class “LinkedListIterator”,
        • Declare the necessary object variables.
        • Define the constructor to create an iterator that points to the front of the linked list.
        • Define the method “next()”,
          • If there is no next element then throws an exception.
          • Assign the position to the front of the linked list.
          • Check if position is null, set the first element to the position.
          • Otherwise, set the next position to the current position.
          • Returns the value.
        • Define the method “hasNext()” that check whether there is next element,
          • Check if position is null,
            • Returns true if first reference is not null.
          • Otherwise,
            • Returns true, if the next reference of the position is not null.
        • Define the method “add()”,
          • If position is null, call the method “addFirst()”.
            • Set the first to the position.
          • Otherwise, create a new node.
            • Assign the element to the new node.
            • Set the next position to the next pointer of the new node.
            • Set the new node value to the next position.
            • Set the new node as the position.
          • Set the Boolean value as false.
        • Define the method “remove()”,
          • Check if there is no next element, throws an exception.
          • If position is same as the first, calls the method “removeFirst()”.
          • Otherwise, set the next position to the previous position.
          • Set the previous to the positions.
          • St the Boolean value to false.
        • Define the method “set()”,
          • If there is no next element, throw an exception.
          • Set the value to the position.

• In a file ListTest.java”, create a class “ListTest”,
  • Define the “main()” method.
    • Create the “LinkedList” object.
    • Call the method “addFirst()” to add “Tommy” to the front of the linked list.
    • Call the method “addFirst()” to add “Juliet” to the font of the linked list.
    • Call the method “addFirst()” to add “Harris” to the font of the linked list.
    • Call the method “addFirst()” to add “David” to the font of the linked list.
    • Assign the value returned from the method “listIterator()” calling by  LinkedList object.
    • Print the actual and expected result.
    • Create “BadLinkedList” object.
    • Call the method “addFirst()” to add “Tommy” to the front of the linked list.
    • Call the method “addFirst()” to add “Juliet” to the font of the linked list.
    • Call the method “addFirst()” to add “Harris” to the font of the linked list.
    • Call the method “addFirst()” to add “David” to the font of the linked list.
    • Assign the value returned from the method “listIterator()” calling by Bad linked list object.
    • Print the actual and expected result.