(gets 1978 copy of The C Programming Language off the shelf) if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) [it's a leap year] else

(gets 1978 copy of The C Programming Language off the shelf) if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) [it's a leap year] else [it's not] I remember this because it is where I first learned the extra rules, beyond just every 4th year.