What is a Function?

A function is a list of statements and local storage, which when given some "information", does some processing and returns a value.

Recall the source code we had for the very simple hello program. There are three functions here:

main() -: this is a special function which every C program must have. It is the function that is started when the program is executed.
func1() -: this is the function I wrote to print the goodbye message. In this case, nothing needs to be given to it, and it has no useful information to return.
printf() -: this is a "built-in" function; part of the C library. It is given the information we want to appear on the screen, and it handles all the details of getting it printed.

Statements:: are the "sentences" of the C language. We will see the kinds of statements we can use in C, together with their "syntax" (grammar), and "semantics" (meaning), as we go through the course.

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