What major would I have to take?

I've always been a fan of computers, programming, technology, and all that stuff. Steve Jobs is one of my biggest inspirations in my life, and I want to get into a career for technology in college. Specifically, I want to be the guy who makes the software of technology. IPhones, for example. I want to be the guy who makes the core of the iPhone. I want to be the guy who programs all the features like Siri, the default apps, fingerprint sensors, control center, all that stuff. I want to be the guy who makes all those kinds of things. The reason why people buy iPhones is for the features, mainly. I want to be the guy who programs those features. I'm very proficient in programming, with things like C++ and java, and all that stuff. What major would I have to take in college to learn this kind of stuff?

From what I've seen, if you're specifically interested in Apple products like the iPhone, not much in college would help you because that's basically Objective-C you're talking about. College curriculums, for the most part, don't offer Objective-C yet, and many don't have a major that is basically software development or application development. The main exceptions are vocational schools or tech schools (Stanford DOES teach Objective-C, or did at one point, at least… But, of course, it's hard to get into Stanford). Most people who go into what you're interested in have Computer Science or Computer Engineering or related degrees, so that's what they major in--and Comp Sci is not tailored to making you a programmer. Still, it would help you if you wanted to work at Apple in the future; it just probably wouldn't teach you Objective-C.

You might end up having to teach yourself, or look specifically for schools that teach classes on programming mobile devices. Personally, when I started learning Objective-C, I mainly self-studied (online class, Udemy, YouTube). It probably wouldn't be that hard for you to learn if you know C++ and Java, because Objective-C derives from C++ and has a lot in common with both of those languages. The Stanford Objective-C class from some years ago is on YouTube in its entirety.

If you want to make the core of the iphone etc, then you would need to get a job at Apple. You better be the top of the class at a tech college like Stanford, MIT, etc, because companies like that hire only the best. That would be a great place to work though!