Contents  Introduction  How to do it  Problems 1 & 2  Problems 3 & 4  Conclusion  Printable version  Discuss this article

Other Considerations

So, your code is nicely split across various files, giving you all the benefits mentioned at the start like increased compilation speed and better organization. Is there anything else you need to know?

Firstly, if you use the C++ standard library, or any other library that uses namespaces, you may find yourself using their identifiers in your header files. If so, don't use the "using" keyword in your headers, as it reduces the effectiveness of namespaces almost to the point of uselessness. Instead, put the using keyword in the source files if necessary, and explicitly qualify the names with their namespace prefix in the header files. Otherwise, when you start using functions that have the same names as the standard library, whether your own or from another library, you'll either have to start renaming them, or go back and edit your header anyway, which in turn will affect all the files that depend on it. Better to do it properly in the first place.

Secondly, the use of macros should be carefully controlled. C programmers have to rely on macros for a lot of functionality, but C++ programmers should avoid them wherever possible. If you want a constant in C++, use the 'const' keyword. If you want an inline function in C++, use the 'inline' keyword. If you want a function that operates on different types in C++, use templates or overloading. But if you need to use a macro for some reason, and you place it in a header file, try not to write macros that could potentially interfere with code in the files that include it. When you get weird compilation errors, you don't want to have to search through every header file to see if someone used a #define to inadvertently change your function or its parameters to something else. So wherever possible, keep macros out of headers unless you can be sure that you don't mind them affecting everything in the project.

Conclusion

If done properly, organizing your files this way can speed your development without hindering you at all or introducing any extra problems. Although it seems like there is a lot to consider when doing so, it becomes second nature in no time. Just remember these key points:

• Split your code up along logical module divisions
• The the interface into the header files and the implementation in the source files
• Use forward declarations wherever possible to reduce dependencies
• Add an inclusion guard to every header file you make
• Don't put code in the headers that might adversely affect source files that include it

Good luck!