What are the characteristics of queues?

The characteristics of the queue are: 1. Only deletion operations are allowed at the front end [front] of the table, while insertion operations are allowed at the back end [rear] of the table; 2. The end where the insertion operation is performed is called a queue. The end that performs the deletion operation is called the head of the queue; 3. When there are no elements in the queue, it is called an empty queue.

The characteristics of the queue are:

The queue is a special linear table. The special thing is that it Only deletion operations are allowed at the front end (front) of the table, and insertion operations are allowed at the back end (rear) of the table. Like the stack, the queue is a linear list with restricted operations. The end that performs the insertion operation is called the tail of the queue, and the end that performs the deletion operation is called the head of the queue. When there are no elements in the queue, it is called an empty queue.

The data elements of the queue are also called queue elements. Inserting a queue element into the queue is called enqueuing, and deleting a queue element from the queue is called dequeuing. Because the queue only allows insertion at one end and deletion at the other end, only the element that enters the queue earliest can be deleted from the queue first, so the queue is also called a first-in-first-out (FIFO—first in first out) linear list.

Extended information

In the circular queue structure, when the last position of the storage space has been used and the queue operation is to be entered again, only the storage space is needed If the first position of the element is free, the element can be added to the first position, that is, the first position of the storage space will be used as the end of the queue. Circular queues make it easier to prevent spurious overflows, but the queue size is fixed.

In the circular queue, when the queue is empty, there is front=rear, and when all the queue space is full, there is also front=rear. In order to distinguish between the two situations, it is stipulated that the circular queue can only have a maximum of MaxSize-1 queue elements. When there is only one empty storage unit left in the circular queue, the queue is full.

Therefore, the condition for the queue to be empty is front=rear, and the condition for the queue to be full is front=(rear 1)%MaxSize.

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