It's really hard to say. All you can really do is be upfront and ask, and believe me, even if it seems like a guy might like you, you can never know until you ask. Trust me, I thought this guy liked me, and it turns out he didn't and so I felt stupid for a little while but we're still good friends so I'm alright. In short, you just can never know until you ask, there are no specific guidelines for how he'll act.
The only way to know for sure is to ask, or to ask them on a date and see if they accept. Conversely they might tell you their feelings or ask you on a date, but don't count on that.