C#-Code

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 WindowsFormsApplication8
{
    public partial class Form1 : Form
    {
        // Initialisierung

        public int iKontostand = 10000;
        Random rnd = new Random();
        public int iZahlUser;
        public int iZufallszahl;
        public int iEinsatz;
        public bool bZahlenGleich;


        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            txt_regeln.Text = "Glücksspiel bei der eine random Zahl zwischen 0 - 9 erzeugt wird.\r\nDer Spieler hat ein Startkonto von 10.000 Punkten und kann damit einen beliebigen Teilbetrag auf die zufällig erzeugte Zahl setzen.\r\nLiegt er richtig bekommt er das 9 Fache seines Einsatzes als Gewinn.\r\n";
            txt_kontostand.Text = Convert.ToString(iKontostand);
        }

        private void txt_regeln_TextChanged(object sender, EventArgs e)
        {
          
        }

        private void txt_kontostand_TextChanged(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
            iZahlUser = Convert.ToInt32(txt_zahlUser.Text);

            iZufallszahl = rnd.Next(0, 9);
            txt_zufallszahl.Text = Convert.ToString(iZufallszahl);

           vergleiche(iZufallszahl , iZahlUser);
            berechne(iKontostand);
            if (iEinsatz < 1)
            {
                this.Close();
            }
            if (iZahlUser < 0 && iZahlUser > 10)
            {
                this.Close();
            }
        }


        public bool vergleiche(int zahl1, int zahl2)
        {
           
            if (zahl1 == zahl2)
            {
                bZahlenGleich = true;
            }
            else
            {
                bZahlenGleich = false;
            }
            return bZahlenGleich;
        }


        public int berechne(int zahl1)
        {
            if (bZahlenGleich)
            {
                iEinsatz = Convert.ToInt32(txt_einsatz.Text);
                iKontostand = iKontostand + (iEinsatz * 9);
                txt_endeSpiel.Text = "gewonnen";
            }
            else
            {
                iEinsatz = Convert.ToInt32(txt_einsatz.Text);
                iKontostand = iKontostand - iEinsatz;
                if (iKontostand <= 0)
                {
                    MessageBox.Show("Sie haben verloren\nKontostand < 0");
                    this.Close();
                }
                txt_endeSpiel.Text = "verloren";
            }
            txt_kontostand.Text = Convert.ToString(iKontostand);

            return iKontostand;
        }
    }
}


namespace WindowsFormsApplication8
{
    partial class Form1
    {
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.label1 = new System.Windows.Forms.Label();
            this.label2 = new System.Windows.Forms.Label();
            this.txt_regeln = new System.Windows.Forms.TextBox();
            this.label3 = new System.Windows.Forms.Label();
            this.label4 = new System.Windows.Forms.Label();
            this.txt_einsatz = new System.Windows.Forms.TextBox();
            this.txt_zahlUser = new System.Windows.Forms.TextBox();
            this.button1 = new System.Windows.Forms.Button();
            this.txt_zufallszahl = new System.Windows.Forms.TextBox();
            this.label5 = new System.Windows.Forms.Label();
            this.txt_kontostand = new System.Windows.Forms.TextBox();
            this.txt_endeSpiel = new System.Windows.Forms.TextBox();
            this.SuspendLayout();
            // 
            // label1
            // 
            this.label1.AutoSize = true;
            this.label1.Font = new System.Drawing.Font("Microsoft Sans Serif", 18.14286F);
            this.label1.ForeColor = System.Drawing.Color.Black;
            this.label1.Location = new System.Drawing.Point(263, 29);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(464, 51);
            this.label1.TabIndex = 0;
            this.label1.Text = "Glücksspiel Zufallszahl";
            // 
            // label2
            // 
            this.label2.AutoSize = true;
            this.label2.Font = new System.Drawing.Font("Microsoft Sans Serif", 12.14286F);
            this.label2.Location = new System.Drawing.Point(22, 152);
            this.label2.Name = "label2";
            this.label2.Size = new System.Drawing.Size(115, 33);
            this.label2.TabIndex = 1;
            this.label2.Text = "Regeln:";
            // 
            // txt_regeln
            // 
            this.txt_regeln.Font = new System.Drawing.Font("Microsoft Sans Serif", 10.14286F);
            this.txt_regeln.Location = new System.Drawing.Point(177, 152);
            this.txt_regeln.Multiline = true;
            this.txt_regeln.Name = "txt_regeln";
            this.txt_regeln.ScrollBars = System.Windows.Forms.ScrollBars.Horizontal;
            this.txt_regeln.Size = new System.Drawing.Size(841, 190);
            this.txt_regeln.TabIndex = 2;
            this.txt_regeln.TextChanged += new System.EventHandler(this.txt_regeln_TextChanged);
            // 
            // label3
            // 
            this.label3.AutoSize = true;
            this.label3.Font = new System.Drawing.Font("Microsoft Sans Serif", 12.14286F);
            this.label3.Location = new System.Drawing.Point(22, 389);
            this.label3.Name = "label3";
            this.label3.Size = new System.Drawing.Size(119, 33);
            this.label3.TabIndex = 3;
            this.label3.Text = "Einsatz:";
            // 
            // label4
            // 
            this.label4.AutoSize = true;
            this.label4.Font = new System.Drawing.Font("Microsoft Sans Serif", 12.14286F);
            this.label4.Location = new System.Drawing.Point(-1, 463);
            this.label4.Name = "label4";
            this.label4.Size = new System.Drawing.Size(138, 33);
            this.label4.TabIndex = 4;
            this.label4.Text = "Ihre Zahl:";
            // 
            // txt_einsatz
            // 
            this.txt_einsatz.Font = new System.Drawing.Font("Microsoft Sans Serif", 12.14286F);
            this.txt_einsatz.Location = new System.Drawing.Point(177, 389);
            this.txt_einsatz.Name = "txt_einsatz";
            this.txt_einsatz.Size = new System.Drawing.Size(346, 40);
            this.txt_einsatz.TabIndex = 5;
            // 
            // txt_zahlUser
            // 
            this.txt_zahlUser.Font = new System.Drawing.Font("Microsoft Sans Serif", 12.14286F);
            this.txt_zahlUser.Location = new System.Drawing.Point(177, 463);
            this.txt_zahlUser.Name = "txt_zahlUser";
            this.txt_zahlUser.Size = new System.Drawing.Size(346, 40);
            this.txt_zahlUser.TabIndex = 6;
            // 
            // button1
            // 
            this.button1.Font = new System.Drawing.Font("Microsoft Sans Serif", 9F);
            this.button1.Location = new System.Drawing.Point(-2, 524);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(139, 48);
            this.button1.TabIndex = 7;
            this.button1.Text = "Zufallszahl:";
            this.button1.UseVisualStyleBackColor = true;
            this.button1.Click += new System.EventHandler(this.button1_Click);
            // 
            // txt_zufallszahl
            // 
            this.txt_zufallszahl.Font = new System.Drawing.Font("Microsoft Sans Serif", 12.14286F);
            this.txt_zufallszahl.Location = new System.Drawing.Point(177, 532);
            this.txt_zufallszahl.Name = "txt_zufallszahl";
            this.txt_zufallszahl.Size = new System.Drawing.Size(346, 40);
            this.txt_zufallszahl.TabIndex = 8;
            // 
            // label5
            // 
            this.label5.AutoSize = true;
            this.label5.Font = new System.Drawing.Font("Microsoft Sans Serif", 18.14286F);
            this.label5.Location = new System.Drawing.Point(671, 385);
            this.label5.Name = "label5";
            this.label5.Size = new System.Drawing.Size(253, 51);
            this.label5.TabIndex = 9;
            this.label5.Text = "Kontostand:";
            // 
            // txt_kontostand
            // 
            this.txt_kontostand.Font = new System.Drawing.Font("Microsoft Sans Serif", 18.14286F);
            this.txt_kontostand.Location = new System.Drawing.Point(673, 475);
            this.txt_kontostand.Name = "txt_kontostand";
            this.txt_kontostand.Size = new System.Drawing.Size(251, 55);
            this.txt_kontostand.TabIndex = 10;
            this.txt_kontostand.TextChanged += new System.EventHandler(this.txt_kontostand_TextChanged);
            // 
            // txt_endeSpiel
            // 
            this.txt_endeSpiel.Font = new System.Drawing.Font("Microsoft Sans Serif", 18.14286F);
            this.txt_endeSpiel.Location = new System.Drawing.Point(38, 642);
            this.txt_endeSpiel.Multiline = true;
            this.txt_endeSpiel.Name = "txt_endeSpiel";
            this.txt_endeSpiel.Size = new System.Drawing.Size(928, 161);
            this.txt_endeSpiel.TabIndex = 11;
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(11F, 24F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(1079, 939);
            this.Controls.Add(this.txt_endeSpiel);
            this.Controls.Add(this.txt_kontostand);
            this.Controls.Add(this.label5);
            this.Controls.Add(this.txt_zufallszahl);
            this.Controls.Add(this.button1);
            this.Controls.Add(this.txt_zahlUser);
            this.Controls.Add(this.txt_einsatz);
            this.Controls.Add(this.label4);
            this.Controls.Add(this.label3);
            this.Controls.Add(this.txt_regeln);
            this.Controls.Add(this.label2);
            this.Controls.Add(this.label1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.Load += new System.EventHandler(this.Form1_Load);
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.Label label2;
        private System.Windows.Forms.TextBox txt_regeln;
        private System.Windows.Forms.Label label3;
        private System.Windows.Forms.Label label4;
        private System.Windows.Forms.TextBox txt_einsatz;
        private System.Windows.Forms.TextBox txt_zahlUser;
        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.TextBox txt_zufallszahl;
        private System.Windows.Forms.Label label5;
        private System.Windows.Forms.TextBox txt_kontostand;
        private System.Windows.Forms.TextBox txt_endeSpiel;
    }
}