//file1.h
#define USD 1
//file2.h
#define UKP 1
//file3
#include
#include
#if !defined (USD) || !defined (UKP)
#error "RROR: NO_CURRENCY rate is specified."
#endif
main() {
int rs;
rs = 10 * currency_rate;
printf ("d\n", rs);
}