Queue/Usage: Difference between revisions

=={{header|Wren}}==

<lang ecmascript>class Queue {

construct new() { _queue = [] }

count { _queue.count }

isEmpty { count == 0 }

clear() { _queue.clear() }

peek { (!isEmpty) ? _queue[0] : null }

push(item) { _queue.add(item) }

pop() {

var item = peek

if (item != null) {

_queue.removeAt(0)

}

return item

}

toList { _queue[0..-1] }

}

var q = Queue.new()

q.push(1)

q.push(2)

System.print("Queue contains %(q.toList)")

System.print("Number of elements in queue = %(q.count)")

var item = q.pop()

System.print("'%(item)' popped from the queue")

System.print("First element is now %(q.peek)")

q.clear()

System.print("Queue cleared")

System.print("Is queue now empty? %((q.isEmpty) ? "yes" : "no")")</lang>

{{out}}

<pre>

Queue contains [1, 2]

Number of elements in queue = 2

'1' popped from the queue

First element is now 2

Queue cleared

Is queue now empty? yes

</pre>