A sentinel is a special value that indicates the _________ of a sequence of items.

A sentinel is a special value that indicates the end of a sequence of items. In computer science, particularly in algorithms and data structures, sentinels are often used to simplify the processing of sequences such as arrays, lists, or other collections. For example, when searching for an item in a list, a sentinel can be placed at the end of the list to avoid checking the bounds of the array during every iteration or recursion. This technique can lead to more efficient code by reducing the number of conditions that need to be evaluated. Sentinels can also provide a clear stopping point for loops, ensuring that the processing of the sequence does not go beyond its intended limits.