BEHIND ALL WELL-WRITTEN PROGRAMS in the C programming language lies the same fundamental element—the function. You’ve used functions in every program that you’ve encountered so far. The
scanf routines are examples of functions. Indeed, each and every program also used a function called
main. So you might ask, what is all the fuss about? The truth is that the program function provides the mechanism for producing programs that are easy to write, read, understand, debug, modify, and maintain. Obviously, anything that can accomplish all of these things is worthy of a bit of fanfare.
First, you must understand what a function is, and then you can proceed to find out how it can be most effectively ...