What is a queqe data structure? Illustrate with a diagram and write the algorithm for inserting data into a circular queue.

 A queue is a linear data structure that follows the FIFO (First In First Out) principle. It is open at both ends and the operations are performed in FIFO order. A circular queue is a variation of a queue in which the last element is connected to the first element to make a circle. This makes it easier to reuse the positions in the array that are left empty after dequeuing elements. The algorithm for inserting data into a circular queue is as follows:

1. Check if the queue is full by comparing the value of rear with front - 1. If it is, then the queue is full and no more elements can be inserted.
2. If the queue is not full, then increment the value of rear by 1 and insert the new element at the position pointed to by rear.
3. If the value of rear becomes equal to the size of the queue, then set rear to 0.
4. If this is the first element being inserted, then set front to 0.

Summary: A queue is a linear data structure that follows the FIFO principle. A circular queue is a variation of a queue in which the last element is connected to the first element to make a circle. The algorithm for inserting data into a circular queue involves checking if the queue is full, incrementing the value of rear, and inserting the new element at the position pointed to by rear. If the value of rear becomes equal to the size of the queue, then set rear to 0. If this is the first element being inserted, then set front to 0.