STL map求value的名次和排序

#include <stdio.h>
#include <string>
#include <stdlib.h>
#include <iostream>
#include <map>
#include <vector>
using namespace std;

typedef map<int, int> templatemap;
templatemap ScoreSort;
int GetPOS(templatemap Sort, int nRoleID)
{
 if (Sort.find(nRoleID) == Sort.end())
  return 0;
 int nPOS = 1;
 int nRoleScore = Sort[nRoleID];
 for (templatemap::iterator iter = Sort.begin(); iter != Sort.end(); iter++)
 {
  int nScore = iter->second;
  if (nRoleScore < nScore)
   nPOS++;
 }
 return nPOS;
}
int main()
{
 for (int i = 0; i < 10; i++)
 {
  int nID = rand()%1000;
  ScoreSort[nID] = rand() % 1000;
 }
 //方法一：只要名次不排序
 for (templatemap::iterator iter = ScoreSort.begin(); iter != ScoreSort.end(); iter++)
 {
  int nScore = iter->second;
  int nPOS = GetPOS(ScoreSort, iter->first);
  cout << "ID:" << iter->first << "分数" << nScore << "名次" << nPOS << endl;
 }
 cout<<"------------------------------------------------"<<endl;
 //方法二：排序且给名次<map>
 templatemap MapSort;
 for (templatemap::iterator iter = ScoreSort.begin(); iter != ScoreSort.end(); iter++)
 {
  int nID = iter->first;
  int nScore = iter->second;
  MapSort[nScore] = nID;
 }
 int j = 0;
 for (templatemap::iterator iter = MapSort.begin(); iter != MapSort.end(); iter++)
 {
  cout << "ID:" << iter->second << "分数" << iter->first << "名次" << MapSort.size()-j << endl;
  j++;
 }
 cout<<"------------------------------------------------"<<endl;
 //方法三：排序且给名次<vector>
 vector<int> vectPOS;
 for (templatemap::iterator iter = ScoreSort.begin(); iter != ScoreSort.end(); iter++)
 {
  int nScore = iter->second;
  vectPOS.push_back(nScore);
 }
 sort(vectPOS.begin(),vectPOS.end());
 for (uint i = 0; i < vectPOS.size(); i++)
 {
  for (templatemap::iterator iter = ScoreSort.begin(); iter != ScoreSort.end(); iter++)
  {
   if(iter->second==vectPOS[i])
   {
    cout << "ID:" << iter->first<< "分数" << iter->second << "名次" << vectPOS.size()-i << endl;
    break;
   }
  }
 }
 getchar();
 return 0;
}