Question

What’s the best way in C++ to copy a pair from a map to vector? I’m doing this so I can subsequently sort the vector.

Answer 1

This should do what you want:

#include <iostream> #include <vector> #include <map> #include <algorithm> #include <iterator>  using namespace std;  bool cmp(const pair<int, int>  &p1, const pair<int, int> &p2) {     return p1.second < p2.second; }  int main() {     map<int, int> m;     for(int i = 0; i < 10; ++i)         m[i] = i * -i;      vector<pair<int, int> > v;     copy(m.begin(), m.end(), back_inserter(v));      sort(v.begin(), v.end(), cmp);      for(int i = 0; i < v.size(); ++i)         cout << v[i].first << ' : ' << v[i].second << endl;     return 0; }