CSCI 270 Programming Assignment #2 Summer
2005
Due: Thursday, July 7
Emphasis: Stacks
In this assignment we will extend the dynamic array implementation of the Stack class given in Figure
7.10 p. 344 and use the Stack to solve some problems. I have provided the DStack header and
implementation file, as well as test driver, as a starting point for your modifications for this
assignment.
Part 1, extension of DStack functionality: In part 1 we will be adding some member functions to the
stack class.
a) Write documentattion, a prototype, and a definition for a member function bottom() for the
DStack classs that returns the bottom element of the stack. Add calls in test driver to test your
bottom() function.
b) Write documentation, a prototype and a definition for a member function nthElement() to
retrieve the nth stack element (counting from the top), leaving the stack without its top n
elements. Add calls in the test driver to test your nthElement() function.
c) The current implementation of push() simply displays an error message and exits if we attempt
to push an item onto an already full stack. Change the implementation of push() to instead
cause the stack to grow whenever it is full. Your implementation should create a new dynamic
array that is double the size of the current stack array whenever a push is attempted on a full
stack. It will need to copy the elements from the old array to the new array, then free up the
memory of the old array by calling delete on it. Add calls in your test driver again to test that
you behavior is correct and that the stack grows appropriately whenever a push is attempted on
a full stack.
Part 2, using DStack to solve a problem. In part 2 we will use the DStack data type in order to solve
a simple problem.
a) Use your DStack class from part 1 to create a function that reads a string, one character at a
time, and determines whether the string contains balanced parentheses, that is, for each left
parenthesis (if there are any) there is exactly one matching right parenthesis later in the string.
Requirements
1) You must start with and modify the DStack class provided for you to implement the additions and
changes in Part 1.
2) For Part 1, turn in your modified DStack.h, DStack.cpp and the DStackTestDriver.cpp that you
changed to satisfy and test your changes for Part 1 a,b and c.
3) For Part 2, create a new .cpp file to implement the parenthesis matching problem. You should
implement the parenthesis matching as a function, that accepts a string as a parameter. The
function will need to create a single DStack object and use it to test the string to see if the
parenthesis are matching. Your function should return a bool value that is true if the parenthesis
matched up in the provided string, and that is false otherwise.
4) Test your function for Part 2 by making up a couple of string examples and calling your function
to test them. Make sure you test some examples of strings with correctly matching parenthesis and
