queue.swift

class Queue {
    var queue: [Int] = []

    func enqueue(_ value: Int) {
        self.queue.append(value)
    }

    func dequeue() {
        self.queue.removeFirst()
    }

    func show() {
        print(self.queue)
    }

    func clear() {
        self.queue = []
    }
}

let queue = Queue()

for n in 0...10 { queue.enqueue(n) }
queue.show()
queue.dequeue()
queue.show()