C #if

The #if preprocessor directive evaluates the expression or condition. If condition is true, it executes the code otherwise #elseif or #else or #endif code is executed.

Syntax:

Syntax with #else:

Syntax with #elif and #else:

C #if example

Let’s see a simple example to use #if preprocessor directive.

Output:

Value of Number is: 0 

Let’s see another example to understand the #if directive clearly.

Output:

2 Value of Number is: 1