Chapter 16, Problem 6PP

Program Plan Intro

Circular singly-linked list

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 “CircularSingleLinkedList.java”, import the package and create a class “CircularSingleLinkedList”,
  • Declare two object variables of type “Node”.
  • Define the constructor to create an empty 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 front of the linked list.
  • Define the method “addLast()”,
    • Call the method “addFirst()”.
    • Assign the value.
      • 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 “CircularSingleLinkedListIterator”,
        • Declare the necessary object variables.
        • Declare the Boolean variable.
        • 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 previous value.
          • Set the Boolean value as true.
          • Check if position is null, set the first element to the position.
          • Otherwise, set the next position to the current position.
          • Returns the value at the position.
            • Define the method “hasNext()” that check whether there is an element after the iteration and before the starting of the list.
            • Define the method “add()”,
              • If position is null,
                • Call the method “addFirst()”.
                • Assign the next value 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 to false.
            • Define the method “remove()”,
              • If there is an element next to the next pointer, throws an exception.
              • Set the next of position to the next of previous position.
              • Set the previous position to the position.
              • Set the Boolean value to false.
            • Define the method “set()”,
              • If there is an element next to the next node, throws an exception.
              • Set the value to the position.
• In a file “CircularSingleListTest.java”, create a class “CircularSingleListTest”,
  • Define the “main()” method.
    • Create “CircularSingleLinkedList” object.
    • Call the method “addFirst()”.
    • Assign the value returned from the method “listIterator()”.
    • Execute a loop,
      • Print the value obtained from the “next()”.
        • • • Print the expected result.
            • Call the method “addFirst()”.
            • Assign the value returned from the method “listIterator()”.
            • Print the value obtained from the “next()”.
            • Execute a loop,
              • Print the space and the result.
            • Print the expected result.
            • Call the method “addLast()” to add the “Harris” to the last in the linked list.
            • Call the method “addLast()” to add the “David” to the last in the linked list.
            • Assign the value returned from the method “listIterator()”.
            • Print the result.
            • Execute a loop,
              • Print the result obtained from the “next()”.
            • Print the expected result.
            • Assign the value returned from the method “listIterator()”.
            • Call the method “next()”.
            • Call the method “next()”.
            • Add more elements after the second element by calling the method “add()” required times.
            • Call the method “next()”.
            • Call the method “remove()”.
            • Assign the value returned from the method “listIterator()”.
            • Print the value obtained from the “next()”.
            • Execute a loop,
              • Print the space and the result obtained from the “next()”.
            • Print the expected result.