multiset 的排序规则

//对结构体排序
// multiset 的排序规则， 如果两个东西的在排序方式中谁排在前面都一样，那么认为他们相等
#include
#include
#include
#include
using namespace std;

struct Student
{
    char name[20];
    int id;
    double gpa;//绩点
};
Student students[] = {
    {"Jack",112,3.4},{"Mary",102,3.8},
    {"Mary",117,3.9},{"Ala",333,3.5},
    {"Zero",101,4.0},{"Cindy",102,4.8}
};

struct Rule {    //按gpa从高到低排序
    bool operator()(const Student & s1, const Student & s2){
        if(s1.gpa != s2.gpa)
            return s1.gpa > s2.gpa;
        else
            return (strcmp(s1.name, s2.name) < 0);
             //分数相等就按姓名排序
    }
};

int main()
{
    multiset st;
    for(int i = 0; i < 5; ++i)
        st.insert(students[i]);

    multiset::iterator p;//迭代器
    for(p = st.begin(); p != st.end(); p++)
        cout << p->gpa << " " << p->name
        << " " << p->id << endl;
    cout << endl;
    //来个假Mary
    Student s = {"Mary", 1000, 3.9};
    p = st.find(s);
    if(p != st.end())
        cout << p->gpa << " " << p->name
        << " " << p->id << endl;


    return 0;
}