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>// pair using 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 way pair<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(); // search while(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：