map vs multimap -- whats the difference?

[CornedBee]

Non-portable random behaviour.

int main() {

        map<int, int> Map;
        Map.insert(pair<int, int>(1,2));
        Map.insert(pair<int, int>(1,3));

        map<int, int>::iterator itr = Map.lower_bound(1);
        cout << itr->second << endl;
        ++itr;
        if(itr == Map.end()) {
                cout << "Thought so." << endl;
        } else {
                cout << itr->second  << endl;
        }

}

Output:

2
Thought so.

Dereferencing the end() iterator yields undefined behaviour.