list-sort2

////////////////////////////////////////
//      2018/04/27 7:36:05
//      list-sort2

// sorts with user datatype
#include <iostream>
#include <iomanip>
#include <list>
#include <string>

using namespace std;

template<class T>
class Member{
private:
    T last_n, first_n;
public:
    Member(T f, T l) :first_n(f), last_n(l){}
    void print();

    // 注意： 由于有两个参数，全局重载
    friend bool operator < (Member& m1, Member& m2){
        return m1.last_n < m2.last_n;
    }
};
//------------------
template<class T>
void Member<T>::print(){
    cout.setf(ios::left);
    cout << setw(15) << last_n << " " << first_n << endl;
}

typedef Member<string> M;
//========================

int main(){
    list<M> li;
    li.push_back(M("Linda", "Smith"));
    li.push_back(M("Frost", "Robert"));
    li.push_back(M("Alex","Amstrong"));

    cout << "Before sorting by last name:\n";
    cout << "==============================" << endl;

    list<M>::iterator it = li.begin();
    while (it != li.end()){
        (it++)->print();
    }
    cout << endl;

    li.sort();

    cout << "After sorting by last name:\n";
    cout << "==========================" << endl;

    it = li.begin();
    while (it != li.end()){
        (it++)->print();
    }
    cout << endl;

    return 0;
}


/*
OUTPUT:
    Before sorting by last name:
    ==============================
    Smith           Linda
    Robert          Frost
    Amstrong        Alex

    After sorting by last name:
    ==========================
    Amstrong        Alex
    Robert          Frost
    Smith           Linda
*/