Today my colleague fixed one bug related to out-of-boundary access of array: a hash function returns the selected index of the array, but the hash function’s return value is int, so in corner case, when the hash value is overflow, it can become negative, and this will cause access an invalid element of the array. The lessons I learnt from this bug:
(1) Review the return value of hash function;
(2) Pay attention to the index when accessing array, is it possible to cause out-of-boundary access?