In ordinary English, a queue is defined as a waiting line, like a line of people waiting to purchase tickets, where the first person in line is the first person served. For computer applications, we similarly define a queue to be a list in which all additions to the list are made at one end, and all deletions from the list are made at the other end. Queues are also called first-in, first-out lists, orFIFO for short. See Figure 3.1