C++ map 自定义排序规则

#include "stdafx.h"
#include <cctype>
#include <map>
#include <algorithm>
#include <string>
#include <iostream>
using namespace std;

// 提供自定义的排序
struct CCaseInsensitive{
bool operator() (const string& str1, const string& str2) const{
string str1NoCase(str1);
string str2NoCase(str2);
transform(str1.begin(), str1.end(), str1NoCase.begin(), tolower);
transform(str2.begin(), str2.end(), str2NoCase.begin(), tolower);
return str1NoCase < str2NoCase;
}
};

//定义StrMapNoCase
typedef map<string, string, CCaseInsensitive> StrMapNoCase;
typedef StrMapNoCase::value_type MapValue;
typedef map<string, string> StrMap;

int main(){
StrMapNoCase map1;
map1.insert(MapValue("John", "5214563"));
map1.insert(MapValue("tom", "5214563"));
map1.insert(MapValue("LiYang", "98874745"));
map1.insert(MapValue("ABC", "98874745"));

StrMap map2;
map2.insert(MapValue("John", "5214563"));
map2.insert(MapValue("tom", "5214563"));
map2.insert(MapValue("LiYang", "98874745"));
map2.insert(MapValue("ABC", "98874745"));

StrMapNoCase::iterator iter1 = map1.find("abc");
if( iter1 != map1.end())
cout << (*iter1).first <<endl;

StrMap::iterator iter2 = map2.find("abc");
if(iter2 != map2.end())
cout << (*iter2).first <<endl;
else
cout << "map2中没有找到abc" << endl;

system("pause");
return 0;
}