Bank med brug af arrays

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Bank_med_arrays
{
    public partial class Form1 : Form
    {
        int[] bankkunder = new int[10];
        public Form1()
        {
            InitializeComponent();
        }

        private void btnOpdater_Click(object sender, EventArgs e)
        {
            int kundenr = int.Parse(txtKundeNr.Text);
            int belob = int.Parse(txtBelob.Text);

            bankkunder[kundenr] = belob;
        }

        private void btnUdskriv_Click(object sender, EventArgs e)
        {
            lstUdskriv.Items.Clear();

            for (int i = 0; i < 10; i++)
            {
                lstUdskriv.Items.Add("Bankkunde nr. " + i.ToString() + " har " + bankkunder[i].ToString() + " kr.");
            }
        }
    }
}