#include <stdio.h>
#include <stdlib.h>
// Declaration
// - what you need when using the function
// (name + parameters and their types + return type)
// Definition
// - what you need when executing the program
// (function's body + Declaration)
void print_val(int x);
int main(int argc, char* argv[]) {
print_val(15);
return 0;
}