//map按值排序
#include <iostream>
#include <string>
#include <vector>
#include <map>
#include <algorithm>
using namespace std;

typedef pair<string, int> PAIR;  

int cmp(const PAIR& x, const PAIR& y)//针对PAIR的比较函数
{  
    return x.second > y.second;  //从大到小
}  

int main() {  
  map<string,int> nmap; 

  nmap["LiMin"] = 90;  
  nmap["ZiLinMi"] = 79;  
  nmap["BoB"] = 92;  
  nmap.insert(make_pair("Bing",99));  
  nmap.insert(make_pair("Albert",86));  
  //把map中元素转存到vector中   
  vector<PAIR> vec(nmap.begin(),nmap.end());
  sort(vec.begin(), vec.end(), cmp); //排序

  for (size_t i = 0; i != vec.size(); ++i) {  //输出
       cout << vec[i].first <<" "<<vec[i].second<<endl;  
  }  

  return 0;  
}

//map按值排序
#include <iostream>
#include <string>
#include <vector>
#include <map>
#include <algorithm>
using namespace std;

struct student{
    string name;
    int score;
};

typedef pair<string, student> PAIR;  


int cmp(const PAIR& x, const PAIR& y)//针对PAIR的比较函数
{  
    return x.second.score > y.second.score;  //从大到小
}  

int main() {  
  map<string,student> nmap; 

  student stu;

  stu.name = "LiMin";
  stu.score = 90;
  nmap.insert(make_pair(stu.name, stu));

  stu.name = "ZiLinMi";
  stu.score = 79;
  nmap.insert(make_pair(stu.name, stu));

  stu.name = "BoB";
  stu.score = 92;
  nmap.insert(make_pair(stu.name, stu));

  stu.name = "Bing";
  stu.score = 99;
  nmap.insert(make_pair(stu.name, stu));

  stu.name = "Albert";
  stu.score = 86;
  nmap[stu.name] = stu;  

  cout <<endl<< "map:"<<endl;    
  for(auto it = nmap.begin(); it != nmap.end(); it++){
       cout<<it->first<<' '<<(it->second).score<<endl;    
  }

  // 把map中元素转存到vector中   
  vector<PAIR> vec(nmap.begin(),nmap.end());

  cout <<endl<< "排序前:"<<endl;  
  for (size_t i = 0; i != vec.size(); ++i) {  //输出
       cout << vec[i].first <<" "<<vec[i].second.score<<endl;  
  }    

  // 排序
  sort(vec.begin(), vec.end(), cmp); 

  cout <<endl<< "排序后vec1:"<<endl;  
  for (size_t i = 0; i != vec.size(); ++i) {  //输出
       cout << vec[i].first <<" "<<vec[i].second.score<<endl;  
  }  

  cout <<endl<< "排序后vec2:"<<endl;  
  // 迭代器
  for (auto it = vec.begin(); it != vec.end(); it++) {  //输出
       cout << (*it).first <<" "<<(*it).second.score<<endl;  
  }  

  return 0;  
}