Guys what was the reason for thiss?

soo there is this guy that i liked all of junior yearr and we had one cl together and he would say hi to me in the hall wayss sometimes..well this year i dont have any cles with him so i never see him, but there are time when i see him in the hall way. Whenever we see each other in the hall way i always try to make eye contact with him but he would never look at me and there were a few times i was walking with my friend who knows him and he would say hi to her and not me and shout "heyy (my friends name) whats up!" and its so weird that he would do that because he knows who i am. so i was really suprised today when i was waiting outside of my clroom for my friend...he walked by and was like "heyyy (my name) whats up!" he hasnt said hi to me in the hallway since september and today he decides to say hi?? i dont get it! what was the reason for him doing this??