Planet CakePHP

I used to think that leap years only happened every four years. In fact, every centennial year that is not evenly divisible by 400 is not a leap year.
I don’t expect to live to 2100, so it shouldn’t matter. But, unfortunately, in programming world, remembering this caveat on the leap year could result in a bug, or worse, world cataclysm like we saw didn’t see with Y2K.
I recently landed this bug and had to write a way out of it. Here’s my solution in PHP, JavaScript, and Cappuccino.

1234567891011function isLeapYear($aYear) {
    if (($aYear % 4) == 0) {
        if (($aYear % 100) == 0 && (($aYear % 400) != 0) {
            return false;
        } else {
            return true;
        }
    } else {
        return false;
    }
}

1234567891011function isLeapYear(aYear) {
    if ((aYear % 4) == 0) {
        if ((aYear % 100) == 0 && ((aYear % 400) != 0) {
            return false;
        } else {
            return true;
        }
    } else {
        return false;
    }
}

1234567891011+ (BOOL)isLeapYear:(int)aYear {
    if ((aYear % 4) == 0) {
        if ((aYear % 100) == 0 && ((aYear % 400) != 0) {
            return NO;
        } else {
            return YES;
        }
    } else {
        return NO;
    }
}