扫描字符串中的某些字符并计算它们

In my AP Computer Science class, we have an assignment where I need to input a string (which in this case is always a tweet) and then check to see if it meets the charlimit, see if it is a retweet, and then count the Hashtags and Mentions. I have figured all of this out, but for a Hashtag or mention to be counted, it has to not have a space or a return following it. My current solution is this:In my AP Computer Science class, we have an ass