Go - Creating Queues

Problem: You want to create a queue data structure.

Solution: Wrap a struct around a slice. Create queue functions on the struct.

 

A queue is a first-in-first-out (FIFO) ordered list. You add elements at the back of the queue and get elements at the front of the queue.

Queues are one of the simplest data structures. They are commonly used as a buffer or queueing system.

Here are the functions associated with a queue:
Enqueue
• Add an element to the back of the queue.
Dequeue
• Remove an element at the front of the queue.
Peek
• Get the element at the front of the queue without removing it from the queue.
Size
• Get the size of the queue.
IsEmpty
• Check if the queue is empty.

You can easily implement a queue using a slice:

type Queue struct {
    elements []any
}

In this code you are using any elements so it can be any type.

func (q *Queue) Enqueue (el any) {
    q.elements = append(q.elements, el)
}

func (q *Queue) Size() int {
    return len(q.elements)
}

func (q *Queue) IsEmpty() bool {
    return q.Size() == 0
}

func (q *Queue) Dequeue() (el any, err error) {
    if q.IsEmpty() {
        err = errors.New("empty queue")
        return
    }
    el = q.elements[0]
    q.elements = q.elements[1:]
    return
}

func (q *Queue) Peek() (el any, err error) {
    if q.IsEmpty() {
        err = errors.New("empty queue")
        return
    }
    el = q.elements[0]
    return
}