Here's the code. A simple use of a for loop. The book I'm reading says that "for (int n = 1; n <= number; n++)" is a valid way of declaring and initializing a variable. There is also a footnote the says "This is a feature added to the 1999 ANSI C Standard (sometimes referred to ad C99). If you're using gcc and you get an error trying to use this feature, try adding the -std=c99 option to the command line." I do get an error and I'm using gcc via Xcode. Is there a #import or something else that adds this feature to Xcode without having to use Terminal?