使用继承的类作为映射值

Question

class StationSongs {
protected:
    int original_song; 
};

class NewsRadio: public StationSongs {
public:
    NewsRadio()
    {
        current_song = NULL;
        currently_empty = 0;
        original_song = 0;
        start_time_of_song = 0;
        next_song_to_play = NULL;
    }
};

class CommercialRadio : public StationSongs {
public:
    CommercialRadio() {
        current_song = NULL;
        currently_empty = 0;
        original_song = 0;
        start_time_of_song = 0;
        next_song_to_play = NULL;
    }
};

问题：我想使用继承的类作为map Value

地图是：

typedef MtmMap<double, StationSongs*> RadioMap;


method{

    CommercialRadio new_station();

    RadioPair new_pair(stationFrequency,*new_station);

    radio.insert(new_pair);
}

我收到此错误：

Multiple markers at this line

- no matching function for call to 'mtm::MtmMap<double, mtm::StationSongs*>::Pair::Pair(double&, 

mtm::CommercialRadio 
     (&)())'

我怎样才能解决这个问题？

Answer 1

CommercialRadio new_station();声明一个函数new_station，它不带参数并返回CommercialRadio。删除括号。 C ++语言的这个属性称为most vexing parse。

此外，基类没有定义虚拟析构函数几乎肯定是错误的。