Iterating in to the set of strings which are the values in map

#include <iostream>

using namespace std;

void insertValue(map<string, set<string> >& myMap,
    string const& key,
    string const& value)
{
    // Check whether there is already a set given the key.
    // If so, insert to the existing set.
    // Otherwise, create a set and add it to the map.
    map<string, set<string> >::iterator found = myMap.find(key);
    if (found != myMap.end())
    {
        cout << "Adding '" << value << "' to an existing set of " << key << "s.\n";
        found->second.insert(value);
    }
    else
    {
        cout << "Adding '" << value << "' to a new set of " << key << "s.\n";
        set<string> temp;
        temp.insert(value);
        myMap.insert(make_pair(key, temp));
    }
}

int main()
{
    map<string, set<string> > filemap;
    insertValue(mymap, "file1", "path1");
    insertValue(mymap, "file1", "path2");
    insertValue(mymap, "file1", "path3");
    insertValue(mymap, "file2", "path1");
    insertValue(mymap, "file3", "path2");
    return 0;
}

Can any one tell how an I iterate through the set of strings, given a key in the above map???? or do I have to place an iterator in the value ....I cant understand how can I go this this further