Detailed Explanation of #else in C Language

The #else preprocessor directive is used to evaluate the case when the #if condition is false. It can be used with the #if, #elif, #ifdef, and #ifndef directives.

Syntax:

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

Syntax with #elif:

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

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C #else Example

Let’s look at a simple example to use the #else preprocessor directive.

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

Output:

Value of Number is non-zero

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