There are numerous shortcoming of the previous (iostreams) approach: 1. Incompatible with dynamically-generated format strings, in which the order of arguments

There are numerous shortcoming of the previous (iostreams) approach: 1. Incompatible with dynamically-generated format strings, in which the order of arguments is different. Example: std::cout << month << '/' << day << '/' << year ... but you now want to adapt that for a non-US locale, e.g. a European one where it's std::cout << day << '/' << month << '/' << year with iostreams, you have to change the code. With C-style printf, you don't (but it's not typeafe and not flexible. But with std::print it could be: std::printf(my_format_str, day, month, year); and `my_format_str` could be either "{0}/{1}/{2}" or "{1}/{0}/{2}". 2. The string allocations which other have mentioned. 3. A lot more typing that is easy to confuse: " << ". 4. The iostreams implementation is super-baroque, with buffer classes nobody uses. and maybe I'm forgetting things.