每个完整周期的c ++

Question

我有一个矢量：

vector<Player> players;
players.push_back(Player(20000));
players.push_back(Player(10000));
players.push_back(Player(12000));
players.push_back(Player(32000));
players.push_back(Player(22000));
players.push_back(Player(18000));

我像这样循环：

for (Player &player : players)
    std::cout << player._gold << endl;

有没有办法命名起始索引并通过玩家完整循环？ 像

//pseudo
    for (Player &player : players, 2)
        std::cout << player._gold << endl;

会给出

12000
32000
22000
18000
20000
10000

请注意，它从第3个元素（索引2）开始，并且它不会在向量的末尾停止。请给我一些关键词或示例如何用c ++中最简单的方式来做。

Answer 1

您需要创建一个适配器对象，例如

template<class T>
class iterator_range
{
private:
    typename T::iterator begin_;
    typename T::iterator end_;
public:
    iterator_range(typename T::iterator b, typename T::iterator e):begin_(b),end_(e)
    {
    }
    typename T::iterator begin() const
    {
        return begin_;
    }

    typename T::iterator end() const
    {
        return end_;
    }
};

您现在可以

for (Player &player : iterator_range(players.begin()+2,players.end()))
    std::cout << player._gold << endl;