Question

Is there a recommended practice that for example global includes shall go befor local includes. By global I mean #include <iostream> and local #include "myhdr.h". Is it some prefered order and why?

Answer 1

Yes, there are recommendations. Some of them are:

• Order: If you’re in MyClass.cpp, put “MyClass.h” first, then C-headers, then STL headers, then your project’s headers.
• Internal order: In each of these categories, use alphabetical order.
• Syntax: Use #inlcude <> for C and STL and #include "" for your own headers.

They should look something like this:

#include "MyClass.h"

#include <time.h>

#include <iostream>
#include <vector>

#include "MyFolder/MyAwesomeClass.h"
#include "MyOtherFolder/MyOtherClass.h"

For more recommendations on good coding style you can take a look at Google’s C++ Style Guide. They give a good explanation on why you should do this in this section.