ARR

using System;

namespace ConsoleApplication2
{
    public class MyArray : IArray
    {
        public int Length { get; }
        public double[] arr = new double[10000];
        int nextIndex = 0;


        public object this[int i]
        {
            get => arr[i];
            set => arr[i] = (int)value;
        }

        public MyArray(int  a)
        {
            this.Length = a;
            this.nextIndex = a;
            this.arr = new double [a];
        }


        public void Add(int value)
        {
            if (nextIndex >= arr.Length)
                throw new IndexOutOfRangeException($"Out of bounds");
            arr[nextIndex] = value;
            ++nextIndex;
        }
    }
}