#include <stdio.h>

int global;

int func1() {
   return global;
}

int& func2() {
   return global;
}

int main(void) {
   global = 23;
   printf("%d\n", global);

   //func1() = 24; // error: expression is not assignable
   func2() = 25; // works!
   printf("%d\n", global);
}