How to check if std::map contains a key without doing insert?

Question

The only way I have found to check for duplicates is by inserting and checking the std::pair.second for false, but the problem is that this still i

Answer 1

Potatoswatter's answer is all right, but I prefer to use find or lower_bound instead. lower_bound is especially useful because the iterator returned can subsequently be used for a hinted insertion, should you wish to insert something with the same key.

map::iterator iter(my_map.lower_bound(key));
if (iter == my_map.end() || key < iter->first) {    // not found
    // ...
    my_map.insert(iter, make_pair(key, value));     // hinted insertion
} else {
    // ... use iter->second here
}