Go cold turkey and stop talking to him for at least a few weeks. Saying hi at school is fine, but no texting, no calling, nothing. It sounds like you may have dumped him, so for his sake (and yours) spare him the teasing that comes with contacting him. And if he dumped you and is still trying to contact you, tell him nicely that he hurt you and you need space to move on.
If you really want to get back together, go ahead and talk and see what happens, BUT, if your trying to get over him, the best thing to do is not talk to him, the more you think about him the worse it is.
The best thing to do is to just move on. It can be hard sometimes because you feel bad after doing it. Try just being friends with him sometimes they might not want to be friends because they are mad that you dumped them. Usually when they still have feelings for you even after you dumped they will go ahead and be friends to be as close as they can to you and hope that one day you guys may come back together.
well me personally I have always remained in good company with any of my exes until recently with my newborns father we still talk becuz he's the3 dad and I don't want him to think I'm keeping him from the baby but he's the only one I never got along with after breaking up.