i don't know the name of some of my friends

How did this happen? I mean, if you get to talk to them, how come the asking of names didn't come up?

If you don't know someone's name you are not friends for real. So I would suggest you to ask for their name.

These people are not actually friends...they are acquaintances. A friend is someone that you actually have a relationship with...someone that you know well and would help out if ever needed...someone that you would turn to if you needed help or support. In other words, you make an effort with them. An acquaintance is just someone you speak to when you see them. It is a casual interaction with no strings of loyalty attached.

That sounds funny. You talk with them many times but still you haven't introduced yourself. I wonder they will also be thinking the same way as you are thinking now. Now in the next meet you should definitely ask their names. Its never too late to ask a name of your friend