map-constructors

////////////////////////////////////////
//      2018/04/30 11:55:43
//      map-constructors

#include <iostream>
#include <map>

using namespace std;

int main(){
    typedef map<int, char, less<int>> M;
    M m1;

    m1.insert(M::value_type(2,'B'));
    m1.insert(M::value_type(3,'C'));
    m1.insert(M::value_type(1,'A'));

    M::iterator it = m1.begin();
    cout << "m1:" << endl;

    while (it != m1.end()){
        cout << (*it).first << "-" << (*it).second << endl;
        it++;
    }
    cout << endl;

    // copy constructor
    M m2(m1);
    it = m2.begin();
    cout << "m2:" << endl;
    while (it != m2.end()){
        cout << (*it).first << "-" << (*it).second << endl;
        it++;
    }
    cout << endl;

    M m3(m2.begin(), m2.end());
    it = m3.begin();
    cout << "m3:" << endl;
    while (it != m3.end()){
        cout << (*it).first << "-" << (*it).second << endl;
        it++;
    }
    return 0;
}

/*
OUTPUT:
    m1:
    1-A
    2-B
    3-C

    m2:
    1-A
    2-B
    3-C

    m3:
    1-A
    2-B
    3-C
*/