Change the current working directory in C++

The chdir function works on both POSIX (manpage) and Windows (called _chdir there but an alias chdir exists).

Both implementations return zero on success and -1 on error. As you can see in the manpage, more distinguished errno values are possible in the POSIX variant, but that shouldn't really make a difference for most use cases.

You want chdir(2). If you are trying to have your program change the working directory of your shell - you can't. There are plenty of answers on SO already addressing that problem.