Exploration 14

The Map Data Structure

Now that you understand the basics, it's time to move on to more exciting challenges.
Let's write a real program--something non-trivial, but still simple enough to master
this early in the book. Your task is to write a program that reads words and counts
the frequency of each unique word. For the sake of simplicity, a word is a string of
non-space characters separated by whitespace. Be aware, however, that by this
definition, words end up including punctuation characters, but we'll worry about
fixing that problem later.

This is a complicated program, touching on everything you've learned about C++ so far.
If you want to exercise your new understanding of file I/O, read from a named file. If
you prefer the simplicity, read from the standard input. Before jumping in and trying
to write a program, take a moment to think about the problem and the tools you need to
solve it. Write pseudo-code for the program. Try to write C++ code where you can, and
make up whatever else you need to tackle the problem. Keep it simple: and don't dwell
on trying to get syntax details correct.
