C++11的enum class有什么改进 强类型枚举的优势解析

enum class

enum

enum class

enum

enum

enum class

enum class

enum class Color { Red, Green, Blue };
enum class TrafficLight { Red, Yellow, Green };

Color myColor = Color::Red;
TrafficLight myLight = TrafficLight::Green;

// 错误：不能直接比较不同类型的 enum class
// if (myColor == myLight) { ... }

// 正确：需要显式转换
if (static_cast<int>(myColor) == static_cast<int>(myLight)) {
    // 不推荐这样做，因为比较的是底层整数值，而不是枚举本身的含义
}

enum class

enum

enum class

enum class

switch

enum class

switch

::

enum class ErrorCode {
    None,
    FileNotFound,
    AccessDenied,
    OutOfMemory
};

ErrorCode checkFile(const std::string& filename) {
    // ... 检查文件是否存在，权限等
    if (/* 文件不存在 */) {
        return ErrorCode::FileNotFound;
    } else if (/* 没有访问权限 */) {
        return ErrorCode::AccessDenied;
    } else {
        return ErrorCode::None;
    }
}

void handleErrorCode(ErrorCode code) {
    switch (code) {
        case ErrorCode::None:
            std::cout << "No error." << std::endl;
            break;
        case ErrorCode::FileNotFound:
            std::cerr << "Error: File not found." << std::endl;
            break;
        case ErrorCode::AccessDenied:
            std::cerr << "Error: Access denied." << std::endl;
            break;
        case ErrorCode::OutOfMemory:
            std::cerr << "Error: Out of memory." << std::endl;
            break;
        default:
            std::cerr << "Unknown error." << std::endl;
            break;
    }
}

int main() {
    ErrorCode result = checkFile("my_file.txt");
    handleErrorCode(result);
    return 0;
}