String Streams (stringstream, istringstream, ostringstream)

String streams treat an in-memory std::string like a file: write to it with <<, read from it with >>, and use the rest of the C++ stream API. They live in the <sstream> header and come in three flavours: std::ostringstream for building strings, std::istringstream for parsing strings, and std::stringstream for both directions. This chapter covers how each one works, when one fits better than the other, and the small set of pitfalls associated with them.