Functions

Relax. We'll talk through this in plain words — no textbook voice.

A function is just a named block of code. Write it once and call it from many places, which cuts down on repeated code and makes the project easier to maintain.

#include <stdio.h>

void showWelcome() {
  printf("Welcome to C functions!
");
}

int main() {
  showWelcome();
  showWelcome();
  return 0;
}

void means the function doesn't return a value. showWelcome() runs the code inside the function every time it's called.

You should see

Welcome to C functions! Welcome to C functions!

Info

Naming a function as an action makes it easier to read. For example, calculateTotal, printMenu, validateInput.

Easy traps

Defining a function doesn't run it — you still have to call it.