The classes aren't usually limited to people majoring in CS. Lots of non-majors take these classes, and the popularity of a class among all students is not cont

The classes aren't usually limited to people majoring in CS. Lots of non-majors take these classes, and the popularity of a class among all students is not controlled by limits on how many can major in CS. In some schools they give CS majors first priority, but there are still all sorts of issues such as scheduling conflicts causing a major to need to sign up for a class late, after it has been opened to non-majors. American universities are not trade schools, and most require their students to take several classes--which students choose for themselves--that are entirely outside their majors. Waves of popularity then rise and fall.