Final answer:
An ordinary queue is a first-in, first-out (FIFO) data structure where the first element added is the first one to be removed.
Step-by-step explanation:
An ordinary queue is indeed a first-in, first-out (FIFO) data structure. This means that the element that is added to the queue first will be the first one to be removed. The queue operates just like a real-life queue, where the person who arrives first is the first to be served.
In a queue, new elements are added at one end (rear) and removed from the other end (front). The process of adding an element to the rear of the queue is called enqueue, while removing an element from the front is called dequeue.
For example, if we have a queue with the elements A, B, C, D in that order, when we dequeue an element, A will be removed and the queue will become B, C, D. The next element to be dequeued will be B, and so on.