• A queue is a First-In/First-Out data structure
• A queue can be used to buffer data that is sent from a fast computer to a slow one. Greatly used in networks.
• A queue can be implemented as a linked list
• When implementing a stack you need to keep track of only one end of the list of items, but when implementing a queue, you need to keep track of both ends of the list.

1. First class goes first and after that by rows
2. People that have kids in Coach class.
3. Coach class goes next by rows from back to front.

Read about Priority queue implementation in the book page 134. Do not focus on the array implementation.