You can have multiple sections of the same course. At the university I went to, there were about ~150 CS students per year. The very largest classes were 50 stu

You can have multiple sections of the same course. At the university I went to, there were about ~150 CS students per year. The very largest classes were 50 students each, with 3 sections of the same course, sometimes taught by the same professor, sometimes taught by different professors. As you progressed through the program, the number of "every CS major takes this course" courses reduced, and most classes were 20-something students.