CS 3100
Fall 2008
  Lab 1
Due Wednesday, September 24

Expression Checker
Based on an assignment created by Dr.  Sarraille and Problem 6 in Chapter 5 of our text book.


Write a program that employs a recursive function to check a series of strings to see if they are well formed expression.


The program reads a series of zero or more strings (strings are separated by white space) from standard input.


The program writes all its output to standard output. First the program writes a heading/greeting message and prompts the user to enter the strings. Next, for each input string, the program goes to a new line of the output, echos (writes) the input string to standard output, goes to a new line again, and prints a message telling whether the string is a well formed expression. Finally the program prints an exit message and stops. There is no other output.

Discussion of Processing:

The following rule defines a well formed expression:

<word> = <dot>| <dash> <word> | <word> <dot>
= .
= -

Your solution to this problem must be "recursive" -- it must include a recursive function that does all the significant work of the program.

This problem is a little like one of the exercises in chapter 5 of Carrano.  You can get some ideas for a solution there. In your solution code, you may want to use the substr method of the string object. See Appendix A of Carrano (Review of C++ Fundamentals) for details.


You need to create a test suite with good data and code coverage.

What To Turn In:

One can solve this problem with a very small program (e.g. just two functions, including main). Do not start coding until you think of a simple algorithm.

Here is the list of things you have to turn in:
  1. At the start of class on the due date, place the following items on the "counter" in front of me:

    Make sure that all of the code and script content shows on the paper. Make sure all content is plainly readable and properly formatted.

  2. Upload to the homework submission system before midnight on the due date:

    Your final source code (example format) and your test script. I will compile and test your programs on the suns in the lab.