C #else:
The #else is a preprocessor directive in C which is used with,
- #if to execute a piece of code, only if the specified condition is FALSE.
- #ifdef to execute a piece of code, only if the specified macro is not defined.
- #ifndef to execute a piece of code, only if the specified macro is defined.
Syntax:
#ifdef MACRO
// code to be executed if macro is defined
#else
// code to be executed if macro is not defined
#endif
OR
#ifndef MACRO
// code to be executed if macro is not defined
#else
// code to be executed if macro is defined
#endif
OR
#if condition
// code to be executed if condition is TRUE.
#else
// code to be executed if condition is FALSE.
#endif
Example:
#include<stdio.h> #define AGE 30 void main() { #if (AGE==20) printf("Value of AGE is correct."); #else printf("Wrong value of AGE."); #endif } |
Output
Wrong value of AGE. |
