try catch finally and arrays in csharp

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 try_catch_array
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        int[] sayi1=new int[5];
        int[] sayi2=new int[5];
        int i = 0,j=0;
        private void btnEkleSayi1_Click(object sender, EventArgs e)
        {
            string sayi = ".sayi";
            sayi1[i] =int.Parse(txtSayi1.Text);
            txtList.Text = txtList.Text + (i+1).ToString()+sayi +"\t"+ sayi1[i].ToString()+ Environment.NewLine;
            txtSayi1.Clear();
            txtSayi1.Focus();
            i++;
        }

        private void btnEkleSayi2_Click(object sender, EventArgs e)
        {
            string bol = ".bolen";
            sayi2[j] = int.Parse(txtSayi2.Text);
            txtList.Text = txtList.Text + (j + 1).ToString()+bol + "\t" + sayi2[j].ToString() + Environment.NewLine;
            txtSayi2.Clear();
            txtSayi2.Focus();
            j++;
        }

        private void btnStart_Click(object sender, EventArgs e)
        {
            try // try to do it // gerçekleþtirmeyi dene
            {
                string result = "result ";
                for (i = 0; i < sayi1.Length; i++)
                {
                    txtList.Text = txtList.Text + result + "\t" + (sayi1[i] / sayi2[i]).ToString() + Environment.NewLine;
                }

            }
            catch(Exception ex) //catch the error // hata yakala
            {
                MessageBox.Show(ex.Message);
            }
            finally // after error message, do that too // hatadan sonra bunu da yap!
            {
                MessageBox.Show("gives error because we defined array[5] but we entered less then five"); 
            }
        }
    }
}