Functions in C

Functions

A function is a reusable, named block of code that performs a specific task. Functions help you avoid repeating code and make programs easier to read and test.

A C function has a return type, a name, a parameter list, and a body.

Syntax

returnType functionName(parameterType param) {
    // code
    return value;
}

Example

add takes two int parameters and returns their sum, which main() then prints.

#include <stdio.h>

int add(int a, int b) {
    return a + b;
}

int main() {
    int result = add(4, 7);
    printf("Sum: %d\n", result);
    return 0;
}

Try it yourself

Copy this example into the C compiler and run it — try changing a value and see what happens.

Quick Quiz