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Looping with variables is probably one of the first programming concepts you learned. You'll be happy to know that Objective-C has for loops—and the syntax is better than that of plain C.
You'll learn all about the NSArray class in the next chapter, but for the moment all you need to know is that it's a class that manages zero or more objects. When you have more than one of something, it's likely that you'll want to loop over the contents at some point.