C++Primer习题10.9

#include<iostream>#include<map>using namespace std;int main(){    map<string,int> word_count;    string word;    while(cin >> word)        ++word_count[word];    map<string,int>::iterator map_it =word_count.begin();    while(map_it != word_count.end())    {          cout << map_it->first << " " << map_it->second << endl;        ++map_it;    }      return 0; }