c++ - How to modify key values in std::map container

Question

Given

std::map<int,std::string> myMap;
fillMyMapWithStuff(myMap);

// modify key values - I need to add a constant value to each key
for (std::map<int,std::string>::iterator mi=myMap.begin(); mi != myMap.end(); ++mi)
{
    // ...
}

Whats a good way apply some re-indexing? Must I remove the old entry and add a new one with the new key and old value?

Answer 1

Looks like you are better off building a new map and swapping it afterward. You'll have only n insert operations instead of n deletions and n insertions.