[sgeisenh]

There is an option to circumvent the prerequisites as a non-major:

  You may also get permission from an advisor if you performed very high on the CS Assessment on Canvas.

I took the course over the summer as a music major and subsequently took several other CS courses as a music major after having a discussion with an advisor in the CS department. I ended up finishing a CS degree a year after my music degree. CMU was really great about providing opportunities for students to explore courses outside of their majors, especially over the summer.

[SoftTalker]

This varies by school. Some will allow you to skip prereqs with instructor or advisor permission, some make that almost impossible. Some may allow you to audit the course but not take it for credit.

Honestly for the larger CS classes I took, there were enough people in the class that I doubt anyone would have noticed a person slipping in to a back row seat and just quietly watching. More than once I sat in on classes that I thought I might want to take, to get a better sense of the content and the professor's teaching style.