Question

Let say if I have a queue of integer (or any class T), can I change the value of the element in the queue?
More specifically, if I define the queue as follow:

Queue<int> q = new Queue<int>();

Can we change the value of its element similar to how we deal with an array? (if q were an array, we would be able to do something like this: q[0]=1 to change its element). I just would like to simplify the scenario and use int as example, but my intention was trying to peek at the 1st item of a class T in a queue, do some calculations and update the queue for other programs to process. I do not want to dequeue it because it the sequence in the queue will then not be the same as the original. Hope what am trying to do make sense. Please advise.

Answer 1

If the item in the queue was a mutable type then you could change the value that the queue has as it’s first item. Without re-creating the queue, or performing a lot of enqueues/dequeues there is no way to change which item is at the front of the queue.

As an example of the first case, if you had a Queue<MyClass> with a definition of:

class MyClass
{
    public string Value { get; set; }
}

Queue<MyClass> queue = new Queue<MyClass>();
queue.Enqueue(new MyClass() { Value = "1" });
queue.Peek().Value = 2;
string value = queue.Peek().Value; // is 2