How to easily indent output to ofstream?

Question

Is there an easy way to indent the output going to an ofstream object? I have a C++ character array that is null terminate and includes newlines. I\'d like to output this

Answer 1

A way to add such feature would be to write a filtering streambuf (i.e. a streambuf which forwards the IO operation to another streambuf but manipulate the data transfered) which add the indentation as part of its filter operation. I gave an example of writing a streambuf here and boost provides a library to help in that.

If your case, the overflow() member would simply test for '\n' and then add the indent just after if needed (exactly what you have done in your indentedOuput function, excepted that newline would be a member of the streambuf). You could probably have a setting to increase or decrease the indent size (perhaps accessible via a manipulator, the manipulator would have to do a dynamic_cast to ensure that the streambuf associated to the stream is of the correct type; there is a mechanism to add user data to stream -- basic_ios::xalloc, iword and pword -- but here we want to act on the streambuf).