Why did this guy avoid eye contact with me when passed each other when he...

...seemed interested? he stared at me a lot in class last semester were in college i even heard him tell his friend whispering that he likes me but when we passed each other in the hall way next semester he would not look me in the eye AT ALL!!!! then all of a sudden he starts like smiling and like blushing he looked really happy and nervous but was smiling into think air no one else was there does he like me or no what can that mean why was he smiling but not looking at me other times he will stare at me when i pass by him and he thinks im not looking,but like now he is AVOIDING ME were going to pass eachother in the hall and i know he saw me coming and then he stopped and talked to his friend that is a girl and he turned his back towards me and they were talking and the whole time she wasnt lookin at him but at me what do you think he told her?? HE AVOIDED ME AND TOLD HER SOMETHING IS THAT BAD?