multimap-constructors

////////////////////////////////////////
//      2018/05/02 15:31:13
//      multimap-constructors
#include <iostream>
#include <map>

using namespace std;

int main(){
    /*

    *   multimap特性以及用法与map完全相同，唯一的差别在于:
    *   允许重复键值的元素插入容器(使用了RB-Tree的insert_equal函数)

    */
    typedef multimap<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'));
    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++;
    }

    // copy constructor
    M m2(m1);

    it = m2.begin();
    cout << "m2:" << endl;
    while (it != m2.end()){
        cout << it->first << "-" << it->second << endl;
        it++;
    }

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

/*
OUTPUT:
    m1:
    1-A
    1-a
    2-B
    3-C
    m2:
    1-A
    1-a
    2-B
    3-C
    m3:
    1-A
    1-a
    2-B
    3-C
*/