C #else

#if expression
//if code
#else
//else code
#endif

#if expression
//if code
#elif expression
//elif code
#else
//else code
#endif

#include <stdio.h>
#include <conio.h>
#define NUMBER 1
void main() {
#if NUMBER==0
printf("Value of Number is: %d",NUMBER);
#else
print("Value of Number is non-zero");
#endif       
getch();
}

Value of Number is non-zero