C# - contador com loop while

Este array de inteiros tem suas posições preenchida 
automaticamente por um contador com laço do while,
o código é didático e totalmente indicado aos 
iniciantes em C#.

//C# contador com loop while

using System;

using System.Drawing;

using System.Windows.Forms;

namespace keypress {

    public partial class Form1 : Form {

        public String str;

        /*============================================================*/

        public void Ini_Array ( ) {

            int [ ] arr = new int [ 100 ];

            int i = 0;

            do {

                arr [ i ] = i;

                if ( arr [ i ] % 10 == 0 ) {

                    str += ( "\n" );

                }

                if ( i >= 0 && i <= 9 )

                    str += ( "0" );

                str += ( arr [ i ] + " " );

                i++;

            } while ( i < 100 );

        }

        /*============================================================*/

        protected override void OnPaint ( PaintEventArgs e ) {

            this.Size = new System.Drawing.Size ( 600, 300 );

            this.Text = "C# contador com loop while";

            this.BackColor = Color.Pink;

            Graphics dc = e.Graphics;

            Pen BluePen = new Pen ( Color.Red, 10 );

            dc.DrawRectangle ( BluePen, 5, 5, 575, 250 );

            Font myFont = new System.Drawing.Font ( "Consolas", 12,

                FontStyle.Italic );

            Brush myBrush = new SolidBrush ( System.Drawing.Color.Black );

            Brush myBrush_1 = new SolidBrush ( System.Drawing.Color.Red );

            dc.DrawString ( "C# contador com loop while",

                myFont, myBrush_1, 180, 15 );

            dc.DrawString ( str, myFont, myBrush, 170, 30 );

        }

        /*============================================================*/

        public Form1 ( ) {

            Ini_Array ( );

        }

    }

    /*============================================================*/

    static class Program {

        /// <summary>

        /// The main entry point for the application.

        /// </summary>

        [STAThread]

        static void Main ( ) {

            Application.EnableVisualStyles ( );

            Application.SetCompatibleTextRenderingDefault ( false );

            Application.Run ( new Form1 ( ) );

        }

    }

}