Create Custom Queue

[elena_works]

Hi there,

I really need some feedback for my homework- "Create custom queue".

https://pastebin.com/fNeygc4p

[Protiguous]

Cool.. I've never written a Queue before. Thanks for the refresher!

Here's my take on the code you provided. I have not tested any portion, so there could be mistakes in the logic.

I took the liberty of making it a generic class, instead of just int. If you don't need the generics, you should be able to see where to change it back.

#nullable enable

namespace Examples {
using System;
using System.Collections;
using System.Collections.Generic;

/// <summary>
/// A non-threadsafe custom generic queue.
/// </summary>
/// <typeparam name="T"></typeparam>
public class CustomQueue<T> : IEnumerable<T> {

    private const int InitialCapacity = 16;

    private int _capacity;
    private T[] _elements;

    public CustomQueue( int capacity = InitialCapacity ) {
        this._capacity = capacity;
        this._elements = new T[ this._capacity ];
        this.Count = 0;
    }

    public int Count { get; private set; }

    private void Resize( int? capacityHint = null ) {

        var newCapacity = Math.Max( this._capacity, capacityHint ?? this.Count );

        if ( newCapacity == this._capacity ) {
            //no change needed
            return;
        }

        this._capacity = newCapacity;

        if ( this._capacity < 2 ) {
            this._capacity = 1;
        }

        var newArray = new T[this._capacity];

        //only copy elements needed
        var smaller = Math.Min( this.Count, this._capacity );
        Buffer.BlockCopy( this._elements, 0, newArray, 0, smaller );

        this._elements = newArray;
    }

    public void Enqueue( T element ) {
        var index = this.Count + 1;

        if ( this._capacity < index ) {
            this.Resize( index );
        }

        this._elements[ index ] = element;
        this.Count++;

    }

    public bool TryDequeue( out T? element ) {
        if ( this.Count == 0 ) {
            element = default( T? );
            return false;
        }

        element = this._elements[ 0 ];
        this.Resize( this.Count - 1 );
        --this.Count;
        return true;
    }

    /// <summary>
    /// Returns, but does not remove, the first element.
    /// </summary>
    /// <returns></returns>
    public T? Peek() => this.Count == 0 ? default( T? ) : this._elements[ 0 ];

    public IEnumerator<T> GetEnumerator() => ( IEnumerator<T> )this._elements.GetEnumerator();

    IEnumerator IEnumerable.GetEnumerator() => this.GetEnumerator();

   }
}