Re: [Boost-users] [lexical_cast] float-to-string rounding error (notfound with cout)

Grant Birchmeier:

I'm seeing unexpected behavior when using lexical_cast<string>.

This code: const float f = 00123.12300; cout << f << endl; cout << boost::lexical_caststd::string(f) << endl; gives the result: 123.123 123.123001

Two questions:

(1) Is there a way to eliminate this trailing '1' with lexical_cast (presumably some wierd rounding error)?

Try this code: float f = 00123.12300; std::cout << f << std::endl; std::cout << boost::lexical_caststd::string(f) << std::endl; float f2 = 123.123001; std::cout << f2 << std::endl; std::cout << boost::lexical_caststd::string(f2) << std::endl; std::cout << f - f2 << std::endl; which will hopefully answer your question.