C++ code file extension? .cc vs .cpp

At the end of the day it doesn't matter because C++ compilers can deal with the files in either format. If it's a real issue within your team, flip a coin and move on to the actual work.

GNU GCC recognises all of the following as C++ files, and will use C++ compilation regardless of whether you invoke it through gcc or g++: .C, .cc, .cpp, .CPP, .c++, .cp, or .cxx.

Note the .C - case matters in GCC, .c is a C file whereas .C is a C++ file (if you let the compiler decide what it is compiling that is).

GCC also supports other suffixes to indicate special handling, for example a .ii file will be compiled as C++, but not pre-processed (intended for separately pre-processed code). All the recognised suffixes are detailed at gcc.gnu.org

Great advice on which to use for the makefile and other tools, considering non-compiler tools while deciding on which extension to use is a great approach to help find an answer that works for you.

I just wanted to add the following to help with some .cc vs .cpp info that I found. The following are extensions broken down by different environments (from the "C++ Primer Plus" book):

Unix uses: .C, .cc, .cxx, .c

GNU C++ uses: .C, .cc, .cxx, .cpp, .c++

Digital Mars uses: .cpp, .cxx

Borland C++ uses: .cpp

Watcom uses: .cpp

Microsoft Visual C++ uses: .cpp, .cxx, .cc

Metrowerks CodeWarrior uses: .cpp, .cp, .cc, .cxx, .c++

The different environments support different extensions. I too was looking to answer this question and found this post. Based on this post I think I might go with .hpp and .cpp for ease of cross-platform/cross-tool recognition.