结构体内重载

struct exam{
    int a, b , c;
    bool operator < (const exam &u)const{
        if(a == u.a && b == u.b) return c > u.c;
        if(a == u.a) return b > u.b;
        else return a > u.a;
    }
}

函数运算符重载

struct exam{
    int a, b , c;
}
bool cmp(const exam &u, const exam &v){
    if(u.a == v.a && u.b == v.b) return u.c > v.c;
        if(u.a == v.a) return u.b > v.b;
        else return u.a > v.a;
}