How can I get the EntryID separately?

[LiKangyuLKY]

With the following code, we can easily get the result of query and print it out. However, how can I get the EntryID separately?

QueryResults ret;
for(size_t i = 0; i < features.size(); i++)
{
    db.query(features[i], ret, 1);
    cout << "Searching for Image " << i << ". " << ret << endl;
}

// searching for image 0 returns 1 result:
// <EntryId: 0, Score: 1>
// searching for image 1 returns 1 result:
// <EntryId: 1, Score: 1>
// searching for image 2 returns 1 result:
// <EntryId: 2, Score: 1>
// searching for image 3 returns 1 result:
// <EntryId: 3, Score: 1>
// searching for image 4 returns 1 result:
// <EntryId: 4, Score: 1>
// searching for image 5 returns 1 result: