Sort by proxy (or: sort one container by the contents of another) in C++

Question

I have a set of data which is split into two arrays (let\'s call them data and keys). That is, for any given item with an index i, I c

Answer 1

You could use a map:

int main() {
  vector keys;
  vector data;
  keys.push_back(5); data.push_back("joe");
  keys.push_back(2); data.push_back("yaochun");
  keys.push_back(1); data.push_back("holio");

  // load the keys and data to the map (they will automatically be inserted in sorted order by key)
  map sortedVals;
  for(int i = 0; i < (int)keys.size(); ++i) {
    sortedVals[keys[i]] = data[i];
  }

  // copy the map values back to vectors  
  int ndx=0;
  for(map::iterator it = sortedVals.begin(); it != sortedVals.end(); ++it) {
    keys[ndx] = it->first;
    data[ndx] = it->second;
    ++ndx;
  }

  // verify
  for(int i = 0; i < (int)keys.size(); ++i) {
    cout<

Here's the output:

---------- Capture Output ----------
> "c:\windows\system32\cmd.exe" /c c:\temp\temp.exe
1 holio
2 yaochun
5 joe

> Terminated with exit code 0.