Question

What happens when front==rear in circular queue

is queue have one element or is full or is empty

Answer 1

It’s ambiguous. You need another mechanism to track whether the queue is full. See the Difficulties section on the Wikipedia page for a discussion.

To quote from that page, here are some ideas on how to solve it:

To solve this problem there are a
number of solutions:
– Always keep one slot open.
– Use a fill count to distinguish the two cases.
– Use read and write counts to get the fill count from.
– Use absolute indices

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