Functions

Functions

A function is a named block of code that runs when you call it. They turn a huge program into tidy reusable pieces.

Defining a function

void myFunction() {
    printf("I just got called!");
}

• void means "returns nothing".
• myFunction is the name.
• The { } hold the body.

Calling a function

int main() {
    myFunction();   // runs the function
    return 0;
}

Put definitions before use

In C, you usually define (or at least declare) a function before calling it. Later we'll meet prototypes that relax this.

Why use functions?

• Reuse: write once, call many times.
• Organization: code is easier to read in chunks.
• Testing: each function can be tested alone.

TL;DR

• A function bundles code under a name.
• Define with a return type, a name, and a body.
• Call it by name with parentheses: myFunction();.
• Functions make code reusable and organized.