Using fputs with an argument of type string

Question

I'm using fputs in C++ to write a string in a file.

fputs (const char*, FILE*);

If I use a simple statement like,

fputs ("information", pFile);

everything is ok and "information" will be written in the file. But if I write a variable of type,

std::vector<std::string>

into the file, some non-ascii characters are stored in the file. Do I have to use a method to convert type std::vector<std::string> into a format which fputs can recognize ?

Answer 1

Use

fprintf ( pFile, "%s", iterVar.at(currentRun).c_str() )

instead of

fprintf ( pFile, "%s", iterVar.at(currentRun).data() )

You don't want to use data() ever as it is missing the trailing \0.

(This code is based on the questioner's comment on @GregHewgill's answer, where iterVar is of type vector<string>.)

Answer 2

That correct, fputs does not understand how a std::vector is laid out in memory.

You should actually have got a compile error when you tried to pass a std::vector to fputs(). Did you try to work around the error by adding a cast or something?