Beginning to 编程

下面是Boost serialization 中的demo例子

为何写了serialize 函数还写个ostream<<

阿，

我对ostream 不是很了解，

我的印象是iostream 是在控制台里输入输出的

/////////////////////////////////////////////////////////////////////////////

class gps_position
{
    friend std::ostream & operator<<(std::ostream &os, const gps_position &gp);
    friend class boost::serialization::access;
    int degrees;
    int minutes;
    float seconds;
    template<class Archive>
    void serialize(Archive & ar, const unsigned int /* file_version */){
        ar & degrees & minutes & seconds;
    }
public:
    // every serializable class needs a constructor
    gps_position(){};
    gps_position(int _d, int _m, float _s) :
        degrees(_d), minutes(_m), seconds(_s)
    {}
};
std::ostream & operator<<(std::ostream &os, const gps_position &gp)
{
    return os << ' ' << gp.degrees << (unsigned char)186 << gp.minutes << '\'' << gp.seconds << '"';
}