map<string,int> m;

map<string,int>::iterator it;//auto it

it = m.begin();

while(it != m.end())

{

    //it->first;

    //it->second;

    it ++;

}

multiset<int>ss;

multiset<int>::iterator it=ss.begin();//auto it,multiset元素可以相同

while(it != ss.end())
{
　　//*it
　　it ++;　
}