1  #include <stdio.h>
 2  
 3  #include <arithmetic/arithmetic.h>
 4  
 5  int main(void) {
 6    int x = 5;
 7    int y = 16;
 8    int z = add(x, y);
 9    printf("%d + %d = %d\n", x, y, z);
10    return 0;
11  }