C++如何使用fstream读取配置文件

std::ifstream file("config.txt");
if (!file.is_open()) {
    std::cerr << "无法打开配置文件！" << std::endl;
    return -1;
}

std::map<std::string, std::string> config;
std::string line;

while (std::getline(file, line)) {
    // 忽略空行或注释（以#开头）
    if (line.empty() || line[0] == '#') continue;

    size_t pos = line.find('=');
    if (pos != std::string::npos) {
        std::string key = line.substr(0, pos);
        std::string value = line.substr(pos + 1);

        // 去除前后空白
        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);

        config[key] = value;
    }
}
file.close();

if (config.find("port") != config.end()) {
    int port = std::stoi(config["port"]);
    std::cout << "端口：" << port << std::endl;
}