Absolutely – you can learn Objective-C without knowing C. And in fact, if you’re interested in learning to build iOS apps, you should just learn Objective-C first – it’ll get you there much more quickly than learning C first, then Objective-C, then the iOS frameworks… I learned Objective-C without knowing C, and I still don’t really know C (despite the fact that I consider myself advanced in Objective-C)…
When I first started learning iOS development, I was a Java developer. And at that point, Java was really the only language I knew. I learned a bit of Groovy (which was so cool in 2009 :) and started replacing my Java with Groovy. But I had never written a line of C or Objective-C when I decided I wanted to learn to build iOS apps.
So I bought Beginning iPhone 3 Development and started working my way through it. As I worked through it, I remember thinking “what’s the deal with these square brackets?” and having tons of other syntax questions. But I kept chugging through the book, working through the exercises in it, and soon had the opportunity to teach a class for developers on getting started with iOS development.
Before I knew it, I was working on an iOS project. And then another, and another. I became competent and then advanced in Objective-C somewhere along the way without ever realizing it. And like I said before, I still don’t really know C.
So yes, you too can learn Objective-C without learning C first. If you’re ready to get started, I’d recommend picking up a copy of Objective-C Programming: The Big Nerd Ranch Guide.
Then start building a simple iOS app – and you’ll be competent in Objective-C before you know it.