multimap的用法示例

本示例代码演示了multimap的构造、插入、遍历、2种查询方法、统计某个key存在的个数等功能。
更多的演示示例代码，请见 《C++标准程序库》，侯捷/孟岩 译

#pragma warning(disable:4786)#include <map>#include <iostream>#include <string>#include <UTILITY>using namespace std;struct userdevice{    string m_devicename;    long m_deviced;    int m_devicePopedom;};typedef multimap<string, userdevice> USERTABLE;        typedef USERTABLE::const_iterator CIT;typedef pair<CIT, CIT> Range;int main(int argc, char* argv[]){    /*    由于键值允许重复插入，在 multimap 容器中具有同一个键值的元素有可能不只一个。    因此，multimap 容器的 find 函数将返回第一个搜索到的元素位置，如果元素不存在，则返回 end 结束元素位置。    equal_range 函数则返回一个可指示相等元素范围区间的 pair 对象。    */    if (1)    {        // 定义一个迭代器        CIT it;        // 定义4个设备        userdevice d1, d2, d3, d4;        d1.m_deviced = 12341234;        d1.m_devicename = "d1";        d1.m_devicePopedom = 123;        d2.m_deviced = 23622344;        d2.m_devicename = "d2";        d2.m_devicePopedom = 234;        d3.m_deviced = 3451234;        d3.m_devicename = "d3";        d3.m_devicePopedom = 345;        d4.m_deviced = 43622344;        d4.m_devicename = "d4";        d4.m_devicePopedom = 456;        //  插入        USERTABLE m_user;        m_user.insert(pair<string, userdevice>("zhangsanfeng",d1));        m_user.insert(pair<string, userdevice>("zhangsanfeng",d2));        m_user.insert(pair<string, userdevice>("zhangsanfeng2",d3));        m_user.insert(pair<string, userdevice>("zhangsanfeng2",d4));        // 遍历        CIT it3 = m_user.begin();        while (it3!=m_user.end())        {            cout<< it3->second.m_deviced <<","                << it3->second.m_devicename.c_str()<<","                << it3->second.m_devicePopedom                << endl;            ++it3;        }        cout<< endl;        // 查找方法一（查找key值是"zhangsanfeng"）        Range range = m_user.equal_range("zhangsanfeng");        for (CIT i = range.first; i!=range.second; ++i)        {            cout<< i->second.m_deviced <<","                << i->second.m_devicename.c_str()<<","                << i->second.m_devicePopedom                << endl;        }        cout<< endl;        // 查找方法二（查找key值是"zhangsanfeng2"）        CIT it2 = m_user.find("zhangsanfeng2");        while(it2!=m_user.end())        {                    cout<< it2->second.m_deviced <<","                << it2->second.m_devicename.c_str()<<","                << it2->second.m_devicePopedom                << endl;            ++it2;        }        cout<< endl;        cout<<"count & size"<<endl;        // 打印键值为 3 的元素个数        cout << m_user.count("zhangsanfeng2") << endl;        // 打印元素个数        cout << m_user.size() << endl;    }    getchar();    return 0;}