How to delete a folder in C++?

I strongly advise to use Boost.FileSystem.

http://www.boost.org/doc/libs/1_38_0/libs/filesystem/doc/index.htm

In your case that would be

boost::filesystem::remove_all(yourPath)

With C++17 you can use std::filesystem, in C++14 std::experimental::filesystem is already available. Both allow the usage of filesystem::remove().

C++17:

#include <filesystem>
std::filesystem::remove("myEmptyDirectoryOrFile"); // Deletes empty directories or single files.
std::filesystem::remove_all("myDirectory"); // Deletes one or more files recursively.

C++14:

#include <experimental/filesystem>
std::experimental::filesystem::remove("myDirectory");

Note 1: Those functions throw filesystem_error in case of errors. If you want to avoid catching exceptions, use the overloaded variants with std::error_code as second parameter. E.g.

std::error_code errorCode;
if (!std::filesystem::remove("myEmptyDirectoryOrFile", errorCode)) {
    std::cout << errorCode.message() << std::endl;
}

Note 2: The conversion to std::filesystem::path happens implicit from different encodings, so you can pass strings to filesystem::remove().