Lab 9

Due 9:40AM November 19, 2008

• Implement a Stack class that stores data using the doubly linked list you implemented for question 1.  Your stack will support the following operations:
  • public void push(Object o) - insert object o on the top of the stack
  • public Object pop() throws StackEmptyException - return the top element on the stack.  If the stack is empty, throw a StackEmptyException.
  • public Object top() throws StackEmptyException - return the top element on the stack without removing it.  If the stack is empty, throw a StackEmptyException.
  • public int size() - return the size of the stack
• Implement a text editor. Your editor will display a string of characters and a cursor. Your program will allow the user to move the cursor and modify the text using the following five operations:
  • right - move the cursor to the right one character or do nothing if at the end of the line
  • left - move the cursor to the left one character or do nothing if at the end of the line
  • rdelete n - delete n characters to the right of the cursor
  • ldelete n - delete n characters to the left of the cursor
  • insert c - insert the character c just before the cursor
  Use 2 stacks to store the characters - one to store the chars to the left of the cursor and one to store the chars to the right of the cursor.
  
• Implement a queue using two stacks.  You queue must support the operations enqueue, dequeue, size, and front.