Functions

Basic example

In C, functions specify the types for their arguments and return value.

float add(int x, int y) {
  return (float)(x + y);
}

• The first type, float is the return type.
• add is the name of the function.
• int x, int y are the parameters to the function, and their types are specified.
• x + y adds the two arguments together.
• (float) casts the result to a float.

Here's the full example:

#include <stdio.h>

float add(int x, int y) {
  return (float)(x + y);
}

int main() {
    float result = add(10, 5);
    printf("result: %f\n", result);
    // result: 15.000000
    return 0;
}

Void

In C, there's a special type for function signatures: void. There are two primary ways you'll use void:

To explicitly state that a function takes no arguments:

int get_integer(void) {
  return 420;
}

When a function doesn't return anything:

void print_integer(int x) {
  printf("this is an int: %d", x);
}

It's important to note that void in C is not like None in Python. It's not a value that can be assigned to a variable. It's just a way to say that a function doesn't return anything or doesn't take any arguments.