STL

STL，算法部分

// 测试数据

typedef struct _data
{
    bool good;
    int num;
    QString desc;
    _data(bool b = false, int n = 0, QString s = "") {
        num = n;
        good = b;
        desc = s;
    }

    bool operator == (_data const &other){
        return other.good == good && other.desc == desc && other.num == num;
    }

    friend QDebug operator << (QDebug os, _data const &other){
        os << other.good << other.num << other.desc;
        return os;
    }

}Data;

class CountIf
{
public:
    CountIf(bool b, int n)
        :m_bFilter(b),m_iNum(n){}
    bool operator()(Data const &other){
        return ((other.good == m_bFilter)&&(other.num == m_iNum));
    }

private:
    bool m_bFilter;
    int m_iNum;
};

    std::vector<Data> vecs;
    vecs.push_back(Data(true,  2, "B"));
    vecs.push_back(Data(false, 1, "C"));
    vecs.push_back(Data(false, 1, "A"));
    vecs.push_back(Data(true, 1, "B"));
    vecs.push_back(Data(false, 2, "A"));
    vecs.push_back(Data(false, 1, "B"));
    vecs.push_back(Data(true, 1, "A"));

    // count_if
    int ret = 0;
    ret = std::count_if(vecs.begin(), vecs.end(), [](Data const &other){
            return other.good == true; //     3
});
    qDebug() << "ves is good , ret = " << ret;
    CountIf filiter(false, 2);
    ret = std::count_if(vecs.begin(), vecs.end(), filiter);
    qDebug() << "vec good && num = 1, ret = " << ret;

    // find
    auto it = std::find(vecs.begin(), vecs.end(), Data(true, 1, "B"));
    if(it!= vecs.end()){
        auto one = *it;
        qDebug() << "find" << one;
    }

    it = std::find_if(vecs.begin(), vecs.end(), [](Data const &other){
            return other.desc == "A";
});
    if(it!= vecs.end()){
        auto one = *it;
        qDebug() << "find" << one;
    }

    //sort 排序（快速排序）
    std::sort(vecs.begin(), vecs.end(), [](Data const &left, Data const &right){
        return left.desc < right.desc;
    });

    for(auto &one : vecs){
        qDebug() << one;
    }

    //stable_sort 稳定排序
    /*
    std::stable_sort(vecs.begin(), vecs.end(), [](Data const &left, Data const &right){
        return left.desc < right.desc;
    });
    for(auto &one : vecs){
        qDebug() << one;
    }
    */

排序中，快排，对于原来相等的元素不保持原有序列，而稳定排序可以为此解决，

addafter。