Chapter 16, Problem 2PP

Program Plan Intro

The methods “get()” and “set()” and a recursive helper method “getNode()”

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 “LinkedList.java”, import the package and create a class “LinkedList”,
  • Declare the object variable.
  • Declare the necessary variable.
  • Define the constructor to create an empty linked list.
  • Define the method “size()” that returns the size of 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 linked list.
  • Define the method “get()” to get the object to the given index.
  • Define the method “set()”  to set the object to the given index.
  • Define the method “getNode()”,
    • Check whether the distance is less than or equal to “0” or start contains null value,
      • If it is true, returns start value.
    • Call the method “getNode()” recursively.
      • • 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.
              • Define the method “hasNext()” that check whether there is next element.
              • 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.
                  • Increment the size.
                • Set the position to the previous node.
              • Define the method “remove()”,
                • If position is same as the previous, throws an exception.
                • If the position is the first position, call the method “removeFirst()”.
                • Otherwise, set the position to the previous position.
                  • Increment the size.
                • Set the previous position to the position.
              • Define the method “set()”,
                • If position is null, throw an exception.
                • Set the value to the position.
• In a file “ListTest.java”, create a class “ListTest”,
  • Define the “main()” method.
    • Create “LinkedList” object.
    • Add the element “Tony” to the linked list.
    • Add the element “Juliet” to the linked list.
    • Add the element “Harris” to the linked list.
    • Add the element “David” to the linked list.
    • Print the element returned from the method “get()”.
    • Print new line.
    • Print expected result.
    • Call the method “set()” to set the element “Jerry” to “2”.
    • Print the element returned from the method “get()”.
    • Print new line.
    • Print expected result.