ENH: Working version based on book example.
ENH: Working version based on book example.

Taken from Programming from the Ground Up
by Jonathan Bartlett, page 39.  Then modified,
and certainly any errors and bad style are the
result of my modifications.

luisibanez/IntroductionToProgramming,luisibanez/IntroductionToProgramming,luisibanez/IntroductionToProgramming,luisibanez/IntroductionToProgramming,luisibanez/IntroductionToProgramming,luisibanez/IntroductionToProgramming,luisibanez/IntroductionToProgramming