and we use it more as you than Mr. It's just a male being generalized as you. i forgot to mention. Instead of saying a man's name it is used 君 . but it is very impolite >.<.

yes the person who answered is right. 君 is not for girls. We use that as a prefix like the english Mr. but it is not used often.

I agree with Taka-san. Here's an example of ”きみ” Professor: きみは何を勉強しているのかね?　(What are you studying?) Student: 日本語を学んでいます。(I'm learning Japanese.) Here's an example of "君" Your friend: 田中君に会った？(Did you meet Tanaka-kun?) You: 会ってないよ。(I didn't.) In this case, Tanaka-kun can be their mutual male friend, a classmate, or someone they casually know.

If it's "きみ," we don't use/hear the word so often in daily conversation. If it's "くん" in "(boys' names)+君," then we use/hear it everyday. When you hear きみ, it's probably when teachers call students at school. It can be used for boys and girls. You don't use 君(くん) for girls' names. :) If I got your question wrong, I apologize and please let me know! ＾＾