Queue

General

Queue is a built-in collection class in Ysharp that implements a first-in, first-out (FIFO) data structure. Elements are added to the end of the queue and removed from the front.

Queue extends the vector protocol, meaning it also supports iteration via foreach.

Note
Some methods have aliases for convenience. For example, enqueue is an alias for add, dequeue is an alias for remove, and isEmpty is an alias for empty.

var queue = new Queue();

Creates a new, empty Queue instance.

var queue = new Queue();

queue.enqueue(1);
queue.enqueue(2);
queue.enqueue(3);

println queue.peek();    // 1
println queue.dequeue(); // 1
println queue.size();    // 2

Reference

Instance methods

Method	Signature	Return Type	Description
add / enqueue	queue.add(value : any)	bool	Inserts a value at the end of the queue
remove / dequeue	queue.remove()	any	Removes and returns the front element; throws if empty
poll	queue.poll()	any | null	Removes and returns the front element, or null if the queue is empty
peek	queue.peek()	any	Returns the front element without removing it; throws if empty
size	queue.size()	int	Returns the number of elements in the queue
isEmpty / empty	queue.isEmpty()	bool	Returns true if the queue is empty
toString	queue.toString()	string	Returns a string representation of the queue

add(value : any) : bool

enqueue(value : any) : bool

• Inserts a value at the end of the queue

var queue = new Queue();

queue.enqueue(10);
queue.enqueue(20);
queue.enqueue(30);

println queue.size(); // 3
println queue.peek(); // 10

remove() : any

dequeue() : any

• Removes and returns the front element; throws if empty

var queue = new Queue();

queue.enqueue(10);
queue.enqueue(20);

println queue.dequeue(); // 10
println queue.size();    // 1

// remove on empty
var emptyQueue = new Queue();

try do
    emptyQueue.remove();
end
catch(e) do
    println e;
end

poll() : any | null

• Removes and returns the front element, or null if the queue is empty

var queue = new Queue();

println queue.poll(); // null

queue.enqueue(10);
queue.enqueue(20);

println queue.poll(); // 10
println queue.poll(); // 20
println queue.poll(); // null

peek() : any

• Returns the front element without removing it; throws if empty

var queue = new Queue();

queue.enqueue(10);
queue.enqueue(20);

println queue.peek(); // 10
println queue.size(); // 2 (unchanged)

// peek on empty
var emptyQueue = new Queue();

try do
    emptyQueue.peek();
end
catch(e) do
    println e;
end

size() : int

• Returns the number of elements in the queue

var queue = new Queue();

println queue.size(); // 0

queue.enqueue(10);
queue.enqueue(20);

println queue.size(); // 2

queue.dequeue();

println queue.size(); // 1

isEmpty() : bool

empty() : bool

• Returns true if the queue is empty

var queue = new Queue();

println queue.isEmpty(); // true
println queue.empty();   // true

queue.enqueue(10);

println queue.isEmpty(); // false
println queue.empty();   // false

queue.dequeue();

println queue.isEmpty(); // true

toString() : string

• Returns a string representation of the queue

var queue = new Queue();

queue.enqueue(10);
queue.enqueue(20);
queue.enqueue(30);

println queue.toString(); // [ 10, 20, 30 ]