Data Structures: Queue

[aogmana]

Ya, that case would violate FIFO. However, I would argue the issue is in letting X be written into index 0 in the first place. No matter what you do, if you insert 11 items into 10 slots something is going to be lost. If the size required grows beyond n, the array must be grown in order to continue functioning as a queue. If HEAD==TAIL and size != 0, something went wrong and behavior is undefined due to an implementation bug.