The new stream classes (iostream, fstream, sstream) can be used convert data to a C++ string for output to standard output, a file, or to a string.

Is this efficient? Are there alternatives?

The C I/O library also can be used to convert data to C-strings

The output C functions are

• printf - output to standard output
• fprintf - output to a file
• sprintf - output to a string

The sprintf function is typically much faster than using a stringstream!

On the other hand, sprintf can only be used with basic types, not class types. While stringstream can be used with any class type, provided operator<< has been overloaded for values of that class type.

On the other, other hand, conversions to string of complicated classes may not be needed in many kinds of applications.