使用ostream和枚举类型重载<<

#include <iostream>

// 定义一个枚举类型
enum Color {
    RED,
    GREEN,
    BLUE
};

// 重载<<运算符
std::ostream& operator<<(std::ostream& os, const Color& color) {
    switch (color) {
        case RED:
            os << "红色";
            break;
        case GREEN:
            os << "绿色";
            break;
        case BLUE:
            os << "蓝色";
            break;
        default:
            os << "未知颜色";
            break;
    }
    return os;
}

int main() {
    Color color = GREEN;
    std::cout << "颜色: " << color << std::endl;
    return 0;
}

颜色: 绿色