Uses of Functions

• In the previous program, power is a function. It takes two arguments, x and n, and returns a value, x ^ n . That's what functions do: they take values (their inputs), and produce outputs (their return value) which other functions (including main) can use.

• The uses of functions are legion.
  • Functions provide a black box abstraction where details can be hiden.
  • Functions enable top down programming, the successive breaking down of a complex task into simpler ones.
  • Functions promote code re-use.
  • Functions allow you to, in effect, add new words to the C language. By building up your own library of useful functions, you can (approximately) create your own language.