Chapter 6, Problem 1D

Explanation of Solution

The two motivations for defining functions in your programs are: 

• Reusability
• Abstraction

The first motivation is reusability:

• Once defined, a function can be used over and over and over again.
• User can save your work by invoking the same function many times in the program.
• Another aspect of reusability is that a single function can be used in several different and separate programs.
• When a user needs to write a new program, user can go back to your old programs, find the functions he/she needs, and reuse those functions in his/her new program.
• User can also reuse functions that somebody else has written...