A boy talked to you three times, but sitting at the next table in the library seemed like he didn't know you. So far, he hasn't asked his name and contact information. What do you mean?
It doesn't make any sense. He took the initiative to talk to you three times to see what the problem was. If he sits at the table next to you and doesn't say hello to you, it means that he has no special thoughts about you. Maybe you think too much, just like you didn't even ask for your phone number, even if you talked for ten times, it wouldn't be interesting.