Rename All Files

Write a program that retrieves all files in a specified directory, sorts them by their size in ascending order, and renames them to file_1, file_2, etc., according to their order. The program should ensure that only regular files (not directories) are renamed.

Hint

• Use the <filesystem> library to work with files and directories.
• Define a custom struct to conveniently store the file path and size.
• Use std::vector to store these structs.
• Use std::sort to order the files (or custom file structs) by size.
• Rename files using std::filesystem::rename.

Answer

#include <iostream>
#include <filesystem>
#include <vector>
#include <algorithm>

struct FileInfo {
    std::filesystem::path filePath;
    uintmax_t fileSize;

    FileInfo(const std::filesystem::path& path, uintmax_t size) : filePath(path), fileSize(size) {}
};

int main() {
    std::string directoryPath;
    std::cout << "Enter the path to the directory: ";
    std::cin >> directoryPath;

    // Vector to store FileInfo structs
    std::vector<FileInfo> files;

    // Iterate through the directory and gather regular files and their sizes
    for (const auto& entry : std::filesystem::directory_iterator(directoryPath)) {
        if (std::filesystem::is_regular_file(entry.path())) {
            files.push_back(FileInfo(entry.path(), std::filesystem::file_size(entry.path())));
        }
    }

    // Sort the files by size
    std::sort(files.begin(), files.end(),
              [](const FileInfo& a, const FileInfo& b) {
                  return a.fileSize < b.fileSize;
              });

    // Rename files in order using indexed loop
    for (int i = 0; i < files.size(); i++) {
        std::filesystem::path newFileName = directoryPath + "/file_" + std::to_string(i + 1);
        std::filesystem::rename(files[i].filePath, newFileName);
    }

    std::cout << "Files have been renamed based on their size." << std::endl;

    return 0;
}