Question

I have a project which has the following directory structure.

root
--include
----module1
----module2
--src
----module1
----module2

So a file say foo.cpp in src/module1 has to include like,

#include "../../include/module1/foo.hpp"

This looks messy and tough to write. I found writing include like

#include <module1/foo.h>

and providing include file search path to root/include when compiling looks neat. However, I am not sure that this style has got any drawbacks.

Which one do you prefer and why? Also do you see any problems in organizing files in the above way?

Answer 1

#include "../../include/module1/foo.hpp"

Specifying paths should be avoided as much as possible. Compilers provide you with a cleaner alternative to achieve the same. Further, a clean design should see to it that you do not need to juggle relative paths for including headers.

A better idea of which one to use (including whether to use quotes or the angle-brackets)
can be had from the standard.

From my copy of the C++ draft:

16.2 Source file inclusion

2 A preprocessing directive of the form

#include <h-char-sequence> new-line`

searches a sequence of
implementation-defined places for a
header identified uniquely by the
specified sequence between the < and >
delimiters, and causes the replacement
of that directive by the entire
contents of the header. How the places
are specified or the header identified
is implementation-defined.

3 A
preprocessing directive of the form

# include "q-char-sequence" new-line 

causes the replacement of that
directive by the entire contents of
the source file identified by the
specified sequence between the ”
delimiters.
The named source file is searched for
in an implementation-defined manner.
If this search is not supported, or if
the search fails, the directive is
reprocessed as if it read

#include <h-char-sequence> new-line`

with the identical contained sequence
(including > characters, if any) from
the original directive.

7 Although an implementation may provide a mechanism for making
arbitrary source files available to
the < > search, in general programmers
should use the < > form for headers
provided with the implementation, and
the ” ” form for sources outside the
control of the implementation.