##### start example #####
spirit@threat:~/develop/example$ cat hello.cpp

#include <stdio.h>
#include <stdlib.h>
#include "var.cpp"
int main(int argc, char *argv[])
{
  printf("Hello world!\n");
  printf("I'm %i years old!\n", var);
  return 1;
}

spirit@threat:~/develop/example$ cat var.cpp

int var = 3;

spirit@threat:~/develop/example$ g++ hello.cpp
spirit@threat:~/develop/example$ ./a.out
Hello world!
I'm 3 years old!
##### end example #####