Thread: problem with if statements (leap year)

Code:

//if year is evenly divisible by 400 OR year is evenly divisible by 4 AND year is not evenly divisible by 100

if(year%400 == 0 || year%4 == 0 && !(year%100 == 0))

Originally Posted by The Brain

Code:

//if year is evenly divisible by 400 OR year is evenly divisible by 4 AND year is not evenly divisible by 100

if(year%400 == 0 || year%4 == 0 && !(year%100 == 0))

You might want to write this as

Code:

if (year%400 == 0 || (year%4 == 0 && year%100 != 0))

since not everyone knows off the top of their head that && has higher precedence than || (I had to look it up).

Edit: If efficiency matters, you can also rewrite it as

Code:

if ((year%4 == 0 && year%100 != 0) || year%400 == 0)

since the first condition is much more likely to be true, allowing the || shortcutting to skip the second condition. The two conditions for && should be left as is, since the first one is much more likely to be false, allowing the && shortcutting to skip the second one.

Originally Posted by radiantarchon28

thnx. i think i was thinking too hard

I feel the same way when it comes to women

since not everyone knows off the top of their head that && has higher precedence than || (I had to look it up).

GCC actually gives a warning about this is you pass it -W -Wall. (That is, || and &&s without parentheses.)