C Tutorial by: Jester

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Functions

C allows you to create your own functions. Functions accept parameters and return a result. They let us simplify our programs into sections that can be called by other sections. Let's have a look at a simple example:

Now remember we said a functions returns a value. We put void because our function doesn't. if we expected it to return an int value, we put int. if a char, we put char, etc. We then declare the name of the function and the code to be executed goes between the curly braces.

Is how we call the function, we must use the () in the call to tell the compiler we're calling a function. Our program uses no parameters and returns no result, it is a very simple function. But it shows you the structure and how to declare one. We could now use this in a program.

Functions allow us to break up the program, if we wanted to print out the info about our program over and over in differen parts of a program, it's easier to use a function and just call it.

Returning a value

Now our function returns a result, it returns an integer. We add 2 and 3 together, assign the result to the_sum and then return it.

Then we write the function that adds to numbers together. Then we open the main() function of our program and assign the result returned from our function to a variable: