#include <stdio.h>

void tofu(int x) {
   x = 371;
}

void tofu2(int &x) {
   x = 371;
}

int main() {
   int a = 23;
   printf("%i\n", a);
   tofu(a);
   printf("%i\n", a);

   printf("\n");

   int a2 = 23;
   printf("%i\n", a2);
   tofu2(a2);
   printf("%i\n", a2);
}