<p>No, you don’t need to reapply. You just need to fill out the major change forms and you’re good to go. In the case of CS (Letters and Science), you don’t even need to have completed the prereqs before switching; you just need to have taken a CS class, I believe. You need to complete the standard engineering prereqs if you want to switch to CSE (College of Engineering), but regardless you can switch as soon as you have them without having to apply.</p>
<p>As for double majors and/or minors, it’s perfectly possible if you’re doing CS. I’m double majoring with linguistics and CS and am on track to graduate in 4 years. If you’re considering any other majors or minors, definitely pick CS over CSE. This also applies if you just prefer flexibility in general.</p>
<p>Note for those confused with the abbreviations, for clarity:
CS refers to computer science within the College of Letters and Science. This has much fewer required units compared to CSE, and has the aforementioned flexibility as a result.
CSE refers to computer science within the College of Engineering. As has been stated, this one is less flexible due to the amount of required units.</p>