C语言 - #if

#if expression
//code
#endif

#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 0
void main() {
  #if (NUMBER==0)
  printf("Value of Number is: %d",NUMBER);
  #endif       
  getch();
}

#include <stdio.h>    
#include <conio.h>    
#define NUMBER 1  
void main() {  
  clrscr();  
  #if (NUMBER==0)  
  printf("1 Value of Number is: %d",NUMBER);  
  #endif  
  
  #if (NUMBER==1)  
  printf("2 Value of Number is: %d",NUMBER);  
  #endif  
  getch();  
}