Getters/Setters with std::vector<>.push_back(…)

问题

For some reason this doesn't work. It compiles file, but no items are added to this vector when using a getter.

E.G.

class class_name {

    public:
        inline std::vector<int> get_numbers() { return m_numbers; }    

    private:
        std::vector<int> m_numbers;
}

....

{
    class_name number_list;
    number_list.get_numbers().push_back(1);
}

If I do it directly (m_numbers.push_back(1)) it works, but if I pull it out with a getter it won't add anything.

回答1:

Return the vector by reference if you plan to modify it:

inline std::vector<int> &get_numbers() { return m_numbers; }  
                        ^

Without the ampersand a copy is returned.

来源：https://stackoverflow.com/questions/12851516/getters-setters-with-stdvector-push-back