FCdemo.cpp

#include <algorithm>
#include <iostream>
#include <set>
#include <unordered_set>
#include <string>
#include <vector>
//  -std=c++11
using namespace std;
//constant
class Person
{
public:
    Person(string lastname, string firstname)
        : _firstname(firstname), _lastname(lastname)
    {
    }
    string firstname() const
    {
        return _firstname;
    }
    string lastname() const
    {
        return _lastname;
    }
private:
    const string _firstname = nullptr;
    const string _lastname = nullptr;
};

class PersonSortCriterion
{
public:
    bool operator()(const Person &p1, const Person &p2) const
    {
        return p1.lastname() < p2.lastname() ||
               (p1.lastname() == p2.lastname() && p1.firstname() < p2.firstname());
    }
};
class PersonSortCriterion1
{
public:
    bool operator()(const Person &p1, const Person &p2) const
    {
        return p1.lastname() > p2.lastname() ||
               (p1.lastname() == p2.lastname() && p1.firstname() > p2.firstname());
    }
};

int main(void)
{
    set<Person, PersonSortCriterion1> coll;
    //unordered_set<Person> coll;
    Person p1("yu", "g");
    Person p2("an", "yu");
    Person p3("xiao", "ming");
    Person p4("xi", "biaoge");
    Person p5("u", "ong");
    coll.insert(p1);
    coll.insert(p2);
    coll.insert(p3);
    coll.insert(p4);
    coll.insert(p5);
    for (auto i : coll)
    {
        cout << i.lastname() << ", " << i.firstname() << endl;
    }

    return 0;
}