Oh ,he is my teacher

I would not feel bad at all yourkl. My dad was a very good teacher. He often deliberatly would throw in something that wasn't right just to see how many of his students were paying attention and how many would speak up and challenge him. See, he taught them to question everything for that is how they learn. Often when a student would question him, it would open up a debate and get the whole class involved and then some real learning took place. He even admitted that there were times when he really was wrong and a studet proved him wrong. That student would get extra credit. If your teacher is angry with you and unable to admit to human error, then he is not a very good teacher.

If you are right ,you should find another ways to persuade your theacher after class. Because you teacher may feel unhappy in the front of your classmate. Consider the situation if you point out the wrong of your boss in the front of your colleague ,you may lose your job. May you will unhappy when someone point out your problem in public. Yes ,nobody is perfect .you are not wrong ,but you need change you ways .

Don't worry too much about that yourkl, you said you just told the truth, so there's nothing wrong with that. Yes sometimes the truth hurts, but it doesn't mean it wouldn't do good. Maye someday he'll realized he will benefit from you telling the truth because he'll be able to make positive changes for the better. Just hang on to the truth buddy. ;-)

Surely nobody is perfect, but it's better to point out his mistake after class.