map::insert and map::find

定义一个map对象，其元素的键是家族姓氏，而值则是用pair类型的对象存储该家族孩子名字和年龄的vector对象，并且可以通过基于家族姓氏的查询输出该家族所有孩子的名字。

[注意]
[1] map对象的类型为 map< string, vector< pair<string, int> > >
[2] pair类型的头文件为utility
[3] map对象的insert操作，m.insert(value_type)，其返回值为pair类型对象：pair<map<xxx,xxx>::iterator,bool>
[4] map对象的find操作，m.find(key)，其返回值为指向该元素的迭代器：map<xxx,xxx>::const_iterator

/*2010-4-10 wcdj*/#include <iostream>#include <map>#include <string>#include <vector>#include <utility>// pairusing namespace std;int main(){map<string, vector<pair<string,int> > > mfamily;string surname;vector<pair<string,int> > pchildren;while (1){cout<<"Enter surname (Ctrl+Z to end): "<<endl;cin>>surname;if(!cin)break;// error, the same surnames maybe have//++mit->first=surname;// -> is prior to ++// ok // first waypair<map<string, vector<pair<string,int> > >::iterator, bool > ret=mfamily.insert(map<string, vector<pair<string,int> > >::value_type(surname,pchildren));// second way/*pair<map<string, vector<pair<string,int> > >::iterator, bool > ret=mfamily.insert(make_pair(surname,pchildren));*/if (!ret.second){cout<<"repeated surname: "<<surname<<endl;continue;}cout<<"Enter every child's name and age of family(Ctrl+Z to end): "<<endl;string childrenName;int nAge;while (cin>>childrenName>>nAge){ret.first->second.push_back(make_pair(childrenName,nAge));}cin.clear();}cin.clear();// searchwhile(1){cout<<"Enter a surname to search(Ctrl+Z to end) : "<<endl;cin>>surname;if(!cin)break;map<string, vector<pair<string,int> > >::const_iterator mit=mfamily.find(surname);if (mit==mfamily.end()){cout<<"no this surname: "<<surname<<endl;} else{cout<<"find this surname: "<<surname<<endl;cout<<"children: "<<endl;vector<pair<string,int> >::const_iterator iter=mit->second.begin();cout<<"name/t/tage"<<endl;for (;iter!=mit->second.end();++iter){cout<<iter->first<<"/t/t"<<iter->second<<endl;//cout<<(*iter).first<<"/t/t"<<(*iter).second<<endl;// same as above}}}system("pause");return 0;}

类似的输出结果：