Exactly. Birthday[0] gives you an out of range exception, since there is no birthday called 0th. Birthdays are [first,second,..] indexed from 1: brithday[1] =

Exactly. Birthday[0] gives you an out of range exception, since there is no birthday called 0th. Birthdays are [first,second,..] indexed from 1: brithday[1] = first, birthday[2] = second, and so on. That's what indexing a series from 1 means.