Rename files with regex and directory_iterator

This is a simple utility that renames files using regular expressions. It uses directory_iterator to find the files in a directory and fs::rename() to rename them.

How to do it…

In this recipe, we create a file rename utility that uses regular expressions:

• We start by defining a few convenience aliases:

  namespace fs = std::filesystem;
  using dit = fs::directory_iterator;
  using pat_v = vector<std::pair<regex, string>>;

The pat_v alias is a vector for use with our regular expressions.

• We also continue to use the formatter specialization for path objects:

  template<>
  struct std::formatter<fs::path>: std::formatter<std::string> {
      template<typename FormatContext>
      auto format(const fs::path& p, FormatContext& ctx) {
          return format_to(ctx.out(), "{}", p.string());...