לפניך שתי מחלקות: המחלקה MyArray והמחלקה Program.

class MyArray
{
    private int[] arr;

    public MyArray(int n)
    {
        arr = new int[n];
        for (int i = 0; i < n; i++)
            if (i % 2 == 0) arr[i] = 1;
            else arr[i] = -1;
    }
    public void One(int n)
    {
        for (int i = 0; i < n; i++)
            arr[i] = int.Parse(Console.ReadLine());
    }
    public void Two()
    {
        for (int i = 0; i < arr.Length; i++)
        {
            Console.WriteLine(i + " " + arr[i]);
        }
    }
    public void Three()
    {
        int lastPlace = arr.Length - 1;
        int halfLen = lastPlace / 2;
        int temp;
        for (int i = 0; i <= halfLen; i++)
        {
            temp = arr[i];
            arr[i] = arr[lastPlace - i];
            arr[lastPlace - i] = temp;
        }
    }
}

class Program
{
    public static void Main(string[] args)
    {
        MyArray star = new MyArray(8);
        Console.WriteLine("--------------------------");
        star.Two();
        star.One(6);
        Console.WriteLine("--------------------------");
        star.Two();
        Console.WriteLine("--------------------------");
        star.Three();
        star.Two();
    }
}