C Tutorial/Preprocessor/if
#if
To define more generalized conditions.
Multiple conditions are connected by relational operators such as AND(&&), OR(||).
#define USA 1
// #define EUP 1
#include <stdio.h>
#if ((1>0) && defined USA)
#define currency_rate 46
#endif
#if (defined (EUP))
#define currency_rate 100
#endif
main()
{
int rs;
rs = 10 * currency_rate;
printf ("%d\n", rs);
}460
