void main() {     vector<int> v;     v.push_back(1);     v.push_back(2);     v.push_back(4);     v.push_back(3);     v.push_back(6);     v.push_back(5);     cout << v.size() <<endl;     vector<int>::iterator it;     for(it = v.begin();it != v.end();)     {           if(*it % 2 == 0)             //v.erase(it++);             //it = v.erase(it);              v.erase(it);         else             it++;     }       cout << v.size() <<endl;     for(it = v.begin();it != v.end();it++)     {           cout << *it << " ";     }       // map的完美删除     map<int, int> m;     m[1] = 1;     m[2] = 2;     m[3] = 4;     m[4] = 3;     m[5] = 5;     m[6] = 6;     cout <<"m size = "<<m.size() <<endl;     map<int, int>::iterator it1;     for(it1 = m.begin(); it1!=m.end();)     {           if(it1->second % 2 == 0)             m.erase(it1++);         else             it1++;     }       cout <<"2的整数倍删除后应该剩下i3";     cout <<"m size = "<<m.size() <<endl; }