Functions in C

In C, executable statements are written inside a function.
A C function is no more than a collection of statements to perform a specific task.

Every C program has at least one function called main()
Bring modularity to your code with the use of functions.
Using functions to break down the functionality of a program can make it easier to debug, modify and it increases the maintainability of the code.
Minimize code size and redundancy.
Provide abstraction with the use of functions.

In C, functions first have to be declared before they are used.

#include <stdio.h>

int myFunctionPrototype(int x, char chr, float num);

int main(){
	int OperationResult;
	OperationResult = myFunctionPrototype(32, 'C', 34.2);
	return 0;
}

int myFunctionPrototype(int x, char chr, float num){
 // do some stuff
 return result;
}

A prototype let's the compiler know about:

The return data type. >> int
The arguments list (and their data type). >> int x, char chr, float num
The order of arguments being passed to the function. >> First an int, then a char and finally a float