Why is setlocale(LC_ALL, "") needed in c++?

Question

C++ / C#

They started teaching programming at the university and I don’t understand why this line is needed, using the Hello world example, it does nothing, and so and so the text is displayed in Russian without errors

Answer 1

Usually, with such tricks, they try (in vain) to force the ancient Windows console to display Russian text. If you develop under MacOS or Linux, then this is useful, for example, for double input-output through a dot, and not through a comma, as it can be by default for the Russian locale.