Functions in C: Learn Types of Functions in C

What is a Function?

A function is a block of code designed to perform a specific task, which can be reused throughout a program.

Function Declaration, Definition, and Call

int add(int a, int b);   // declaration

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

int main() {
    int result = add(5, 3); // function call
}

Types of Functions in C

• Library functions — predefined functions like printf(), strlen().
• User-defined functions — functions written by the programmer.
• Functions with/without arguments — may or may not accept input parameters.
• Functions with/without return values — may or may not return a value using return.