It may not be clear why it is worth the trouble to divide a program into functions.
There are several reasons:
• Creating a new function gives you an opportunity to name a group of statements,
which makes your program easier to read, understand, and debug.
• Functions can make a program smaller by eliminating repetitive code. Later,
if you make a change, you only have to make it in one place.
• Dividing a long program into functions allows you to debug the parts one at
a time and then assemble them into a working whole.
• Well-designed functions are often useful for many programs. Once you write
and debug one, you can reuse it.
Throughout the rest of the book, often we will use a function definition to explain
a concept. Part of the skill of creating and using functions is to have a function
properly capture an idea such as “find the smallest value in a list of values”. Later
we will show you code that finds the smallest in a list of values and we will present
it to you as a function named min which takes a list of values as its argument and
returns the smallest value in the list.
