c++中如何从文件加载map_c++ map文件加载实现

#include 

void loadMapFromFile(std::map& data, const std::string& filename) {
    std::ifstream in(filename);
    if (!in.is_open()) return;

    std::string key, value;
    while (in >> key >> value) {
        data[key] = value;
    }
    in.close();
}

void loadMapWithSpaces(std::map& data, const std::string& filename) {
    std::ifstream in(filename);
    std::string line;

    while (std::getline(in, line)) {
        size_t pos = line.find(':');
        if (pos != std::string::npos) {
            std::string key = line.substr(0, pos);
            std::string value = line.substr(pos + 1);
            // 去除首尾空格（可选）
            key.erase(0, key.find_first_not_of(" \t"));
            key.erase(key.find_last_not_of(" \t") + 1);
            value.erase(0, value.find_first_not_of(" \t"));
            value.erase(value.find_last_not_of(" \t") + 1);
            data[key] = value;
        }
    }
    in.close();
}

void saveMapWithSpaces(const std::map& data, const std::string& filename) {
    std::ofstream out(filename);
    for (const auto& pair : data) {
        out << pair.first << ":" << pair.second << "\n";
    }
    out.close();
}

void saveMapBinary(const std::map& data, const std::string& filename) {
    std::ofstream out(filename, std::ios::binary);
    uint32_t size = data.size();
    out.write(reinterpret_cast(&size), sizeof(size));
    for (const auto& pair : data) {
        out.write(reinterpret_cast(&pair.first), sizeof(pair.first));
        out.write(reinterpret_cast(&pair.second), sizeof(pair.second));
    }
    out.close();
}

void loadMapBinary(std::map& data, const std::string& filename) {
    std::ifstream in(filename, std::ios::binary);
    uint32_t size;
    in.read(reinterpret_cast(&size), sizeof(size));
    data.clear();

    int key, value;
    for (uint32_t i = 0; i < size; ++i) {
        in.read(reinterpret_cast(&key), sizeof(key));
        in.read(reinterpret_cast(&value), sizeof(value));
        data[key] = value;
    }
    in.close();
}