What are the best practices for using C++ preprocessor directives?

What are the best practices for using C++ preprocessor directives?

When using C++ preprocessor directives, it's best to limit their use to avoid code complexity. Use include guards to prevent multiple inclusions, and prefer #define for constants over macros.

Can you explain what include guards are?

Include guards are preprocessor directives that prevent a header file from being included multiple times. They typically look like this:

#ifndef HEADER_FILE_NAME_H
#define HEADER_FILE_NAME_H

// Your code here

#endif // HEADER_FILE_NAME_H

Are there any specific directives I should avoid?

Yes, avoid using #define for anything other than constants, as it can lead to hard-to-debug issues. Instead, use const or constexpr for constants.

What about conditional compilation?

Conditional compilation can be useful for including or excluding code based on certain conditions, but use it sparingly to keep your codebase clean and maintainable.