1 #ifndef _CVALUEFIND_H_ 2 #define _CVALUEFIND_H_ 3 #include <string> 4 #include <algorithm> 5 #include <map> 6  7  8 class map_value_finder 9 {10 public:11     map_value_finder(const std::string &cmp_string):m_s_cmp_string(cmp_string){}12     bool operator ()(const std::map<int, std::string>::value_type &pair)13     {14         return pair.second == m_s_cmp_string;15     }16 private:17     const std::string &m_s_cmp_string;                    18 };19 #endif

#include <iostream>#include <windows.h>#include <vector>#include "CValueFind.h"using namespace std;//map按value值查找——find_if的使用int main(){    std::map<int, std::string> my_map;    my_map.insert(std::make_pair(10, "china"));    my_map.insert(std::make_pair(20, "usa"));    my_map.insert(std::make_pair(30, "english"));    my_map.insert(std::make_pair(31, "english"));    my_map.insert(std::make_pair(32, "english"));    my_map.insert(std::make_pair(33, "english"));    my_map.insert(std::make_pair(34, "english"));    my_map.insert(std::make_pair(35, "english"));    my_map.insert(std::make_pair(36, "english"));    my_map.insert(std::make_pair(37, "english"));    my_map.insert(std::make_pair(38, "english"));    my_map.insert(std::make_pair(39, "english"));    my_map.insert(std::make_pair(40, "hongkong"));     std::map<int, std::string>::iterator it = my_map.end();    it = std::find_if(my_map.begin(), my_map.end(), map_value_finder("english"));    if (it == my_map.end())        printf("not found\n");           else    {        printf("found key:%d value:%s\n", it->first, it->second.c_str());    }    getchar();    return 0;}