下面是游戲的源代碼。有兩個文件：main.cs 和 snake.cs

//
// main.cs begin
//
using system;
using system.drawing;
using system.collections;
using system.componentmodel;
using system.windows.forms;
using system.data;
using system.threading;

namespace greedysnake
{
 ///
 /// formmain 的摘要說明。
 ///
 public class formmain : system.windows.forms.form
 {
  ///
  /// 必需的設計器變量。
  ///
  private system.componentmodel.container components = null;
  private system.windows.forms.menuitem menugame;
  private system.windows.forms.menuitem menugamebegin;
  private system.windows.forms.menuitem menugameend;
  private system.windows.forms.mainmenu menumain;
  private system.windows.forms.menuitem menugamerebegin;
  private system.windows.forms.menuitem menuoption;
  private system.windows.forms.menuitem menuoptiontopmost;

  private system.windows.forms.menuitem menuoptiongamedifficulty;
  private system.windows.forms.menuitem menuoptionsplit;
  private system.windows.forms.menuitem menuoptiongamedifficultyeasy;
  private system.windows.forms.menuitem menuoptiongamedifficultycommon;
  private system.windows.forms.menuitem menuoptiongamedifficultydifficult;

  private system.windows.forms.panel panelgameregion;
  private system.windows.forms.panel panel1;
  private system.windows.forms.label labelgamedifficulty;
  private system.windows.forms.label labelgamecurrentdifficulty;
  private system.windows.forms.label labelgameintroduce;
  private system.windows.forms.label labelup;
  private system.windows.forms.label labeldown;
  private system.windows.forms.label labelleft;
  private system.windows.forms.label labelright;
  private system.windows.forms.label labelstatistic;
  private system.windows.forms.label labelinitcount;
  private system.windows.forms.label labelcurrentcount;
  private system.windows.forms.label labelscore;
 
  private system.windows.forms.label labeleatgreencount;

  private const int cispeed = 80; // 游戲速度（默認難度：一般）
  private int ispeed = cispeed;  // 游戲速度

  private const int icount = 18;  // 蛇長
  private const int iradius = 5;  // 蛇骨接的半徑
  private const int istep = 2 * iradius;  // 兩個相鄰的蛇骨中心相差的距離

  private const int imaxcount = 5;  // 最多能剩下的食物總數

  private snake snake;
  private snakefood snakefood;

  public formmain()
  {
   //
   // windows 窗體設計器支持所必需的
   //
   initializecomponent();

   //
   // todo: 在 initializecomponent 調用后添加任何構造函數代碼
   //
  }

  #region 清理正在使用的資源
  ///
  /// 清理所有正在使用的資源。
  ///
  protected override void dispose( bool disposing )
  {
   if( disposing )
   {
    if (components != null)
    {
     components.dispose();
    }
   }
   base.dispose( disposing );
  }
  #endregion

  #region windows 窗體設計器生成的代碼
  ///
  /// 設計器支持所需的方法 - 不要使用代碼編輯器修改
  /// 此方法的內容。
  ///
  private void initializecomponent()
  {
   this.menumain = new system.windows.forms.mainmenu();
   this.menugame = new system.windows.forms.menuitem();
   this.menugamebegin = new system.windows.forms.menuitem();
   this.menugamerebegin = new system.windows.forms.menuitem();
   this.menugameend = new system.windows.forms.menuitem();
   this.menuoption = new system.windows.forms.menuitem();
   this.menuoptiongamedifficulty = new system.windows.forms.menuitem();
   this.menuoptiongamedifficultyeasy = new system.windows.forms.menuitem();
   this.menuoptiongamedifficultycommon = new system.windows.forms.menuitem();
   this.menuoptiongamedifficultydifficult = new system.windows.forms.menuitem();
   this.menuoptionsplit = new system.windows.forms.menuitem();
   this.menuoptiontopmost = new system.windows.forms.menuitem();
   this.panelgameregion = new system.windows.forms.panel();
   this.panel1 = new system.windows.forms.panel();
   this.labelscore = new system.windows.forms.label();
   this.labeleatgreencount = new system.windows.forms.label();
   this.labelcurrentcount = new system.windows.forms.label();
   this.labelinitcount = new system.windows.forms.label();
   this.labelstatistic = new system.windows.forms.label();
   this.labelright = new system.windows.forms.label();
   this.labelleft = new system.windows.forms.label();
   this.labeldown = new system.windows.forms.label();
   this.labelup = new system.windows.forms.label();
   this.labelgameintroduce = new system.windows.forms.label();
   this.labelgamecurrentdifficulty = new system.windows.forms.label();
   this.labelgamedifficulty = new system.windows.forms.label();
   this.panel1.suspendlayout();
   this.suspendlayout();
   //
   // menumain
   //
   this.menumain.menuitems.addrange(new system.windows.forms.menuitem[] {
                      this.menugame,
                      this.menuoption});
   //
   // menugame
   //
   this.menugame.index = 0;
   this.menugame.menuitems.addrange(new system.windows.forms.menuitem[] {
                      this.menugamebegin,
                      this.menugamerebegin,
                      this.menugameend});
   this.menugame.text = "游戲(&g)";
   //
   // menugamebegin
   //
   this.menugamebegin.index = 0;
   this.menugamebegin.text = "開始(&s)";
   this.menugamebegin.click += new system.eventhandler(this.menugamebegin_click);
   //
   // menugamerebegin
   //
   this.menugamerebegin.enabled = false;
   this.menugamerebegin.index = 1;
   this.menugamerebegin.text = "重新開始（&r）";
   this.menugamerebegin.click += new system.eventhandler(this.menugamerebegin_click);
   //
   // menugameend
   //
   this.menugameend.index = 2;
   this.menugameend.text = "結束(&x)";
   this.menugameend.click += new system.eventhandler(this.menugameend_click);
   //
   // menuoption
   //
   this.menuoption.index = 1;
   this.menuoption.menuitems.addrange(new system.windows.forms.menuitem[] {
                        this.menuoptiongamedifficulty,
                        this.menuoptionsplit,
                        this.menuoptiontopmost});
   this.menuoption.text = "選項(&o)";
   //
   // menuoptiongamedifficulty
   //
   this.menuoptiongamedifficulty.index = 0;
   this.menuoptiongamedifficulty.menuitems.addrange(new system.windows.forms.menuitem[] {
                          this.menuoptiongamedifficultyeasy,
                          this.menuoptiongamedifficultycommon,
                          this.menuoptiongamedifficultydifficult});
   this.menuoptiongamedifficulty.text = "游戲難度";
   //
   // menuoptiongamedifficultyeasy
   //
   this.menuoptiongamedifficultyeasy.index = 0;
   this.menuoptiongamedifficultyeasy.radiocheck = true;
   this.menuoptiongamedifficultyeasy.text = "容易";
   this.menuoptiongamedifficultyeasy.click += new system.eventhandler(this.menuoptiongamedifficultyeasy_click);
   //
   // menuoptiongamedifficultycommon
   //
   this.menuoptiongamedifficultycommon.checked = true;
   this.menuoptiongamedifficultycommon.index = 1;
   this.menuoptiongamedifficultycommon.radiocheck = true;
   this.menuoptiongamedifficultycommon.text = "一般";
   this.menuoptiongamedifficultycommon.click += new system.eventhandler(this.menuoptiongamedifficultycommon_click);
   //
   // menuoptiongamedifficultydifficult
   //
   this.menuoptiongamedifficultydifficult.index = 2;
   this.menuoptiongamedifficultydifficult.radiocheck = true;
   this.menuoptiongamedifficultydifficult.text = "極難";
   this.menuoptiongamedifficultydifficult.click += new system.eventhandler(this.menuoptiongamedifficultydifficult_click);
   //
   // menuoptionsplit
   //
   this.menuoptionsplit.index = 1;
   this.menuoptionsplit.text = "-";
   //
   // menuoptiontopmost
   //
   this.menuoptiontopmost.index = 2;
   this.menuoptiontopmost.text = "總在最前面";
   this.menuoptiontopmost.click += new system.eventhandler(this.menuoptiontopmost_click);
   //
   // panelgameregion
   //
   this.panelgameregion.anchor = ((system.windows.forms.anchorstyles)((((system.windows.forms.anchorstyles.top | system.windows.forms.anchorstyles.bottom)
    | system.windows.forms.anchorstyles.left)
    | system.windows.forms.anchorstyles.right)));
   this.panelgameregion.backcolor = system.drawing.color.black;
   this.panelgameregion.borderstyle = system.windows.forms.borderstyle.fixed3d;
   this.panelgameregion.location = new system.drawing.point(8, 16);
   this.panelgameregion.name = "panelgameregion";
   this.panelgameregion.size = new system.drawing.size(500, 540);
   this.panelgameregion.tabindex = 0;
   //
   // panel1
   //
   this.panel1.anchor = ((system.windows.forms.anchorstyles)(((system.windows.forms.anchorstyles.top | system.windows.forms.anchorstyles.bottom)
    | system.windows.forms.anchorstyles.right)));
   this.panel1.controls.add(this.labelscore);
   this.panel1.controls.add(this.labeleatgreencount);
   this.panel1.controls.add(this.labelcurrentcount);
   this.panel1.controls.add(this.labelinitcount);
   this.panel1.controls.add(this.labelstatistic);
   this.panel1.controls.add(this.labelright);
   this.panel1.controls.add(this.labelleft);
   this.panel1.controls.add(this.labeldown);
   this.panel1.controls.add(this.labelup);
   this.panel1.controls.add(this.labelgameintroduce);
   this.panel1.controls.add(this.labelgamecurrentdifficulty);
   this.panel1.controls.add(this.labelgamedifficulty);
   this.panel1.location = new system.drawing.point(515, 8);
   this.panel1.name = "panel1";
   this.panel1.size = new system.drawing.size(104, 545);
   this.panel1.tabindex = 3;
   //
   // labelscore
   //
   this.labelscore.forecolor = system.drawing.color.white;
   this.labelscore.location = new system.drawing.point(8, 184);
   this.labelscore.name = "labelscore";
   this.labelscore.size = new system.drawing.size(88, 16);
   this.labelscore.tabindex = 11;
   this.labelscore.textalign = system.drawing.contentalignment.middleright;
   //
   // labeleatgreencount
   //
   this.labeleatgreencount.forecolor = system.drawing.color.green;
   this.labeleatgreencount.location = new system.drawing.point(8, 168);
   this.labeleatgreencount.name = "labeleatgreencount";
   this.labeleatgreencount.size = new system.drawing.size(88, 16);
   this.labeleatgreencount.tabindex = 10;
   this.labeleatgreencount.textalign = system.drawing.contentalignment.middleright;
   //
   // labelcurrentcount
   //
   this.labelcurrentcount.forecolor = system.drawing.color.white;
   this.labelcurrentcount.location = new system.drawing.point(8, 144);
   this.labelcurrentcount.name = "labelcurrentcount";
   this.labelcurrentcount.size = new system.drawing.size(88, 16);
   this.labelcurrentcount.tabindex = 9;
   this.labelcurrentcount.textalign = system.drawing.contentalignment.middleright;
   //
   // labelinitcount
   //
   this.labelinitcount.forecolor = system.drawing.color.white;
   this.labelinitcount.location = new system.drawing.point(8, 119);
   this.labelinitcount.name = "labelinitcount";
   this.labelinitcount.size = new system.drawing.size(88, 16);
   this.labelinitcount.tabindex = 8;
   this.labelinitcount.textalign = system.drawing.contentalignment.middleright;
   //
   // labelstatistic
   //
   this.labelstatistic.font = new system.drawing.font("隸書", 12f, system.drawing.fontstyle.regular, system.drawing.graphicsunit.point, ((system.byte)(134)));
   this.labelstatistic.forecolor = system.drawing.color.white;
   this.labelstatistic.location = new system.drawing.point(8, 80);
   this.labelstatistic.name = "labelstatistic";
   this.labelstatistic.size = new system.drawing.size(88, 32);
   this.labelstatistic.tabindex = 7;
   this.labelstatistic.text = "游戲統計:";
   this.labelstatistic.textalign = system.drawing.contentalignment.middleleft;
   //
   // labelright
   //
   this.labelright.forecolor = system.drawing.color.white;
   this.labelright.location = new system.drawing.point(8, 408);
   this.labelright.name = "labelright";
   this.labelright.size = new system.drawing.size(88, 23);
   this.labelright.tabindex = 6;
   this.labelright.text = "d(right)  右";
   this.labelright.textalign = system.drawing.contentalignment.middleright;
   //
   // labelleft
   //
   this.labelleft.forecolor = system.drawing.color.white;
   this.labelleft.location = new system.drawing.point(8, 376);
   this.labelleft.name = "labelleft";
   this.labelleft.size = new system.drawing.size(88, 23);
   this.labelleft.tabindex = 5;
   this.labelleft.text = "a(left)   左";
   this.labelleft.textalign = system.drawing.contentalignment.middleright;
   //
   // labeldown
   //
   this.labeldown.forecolor = system.drawing.color.white;
   this.labeldown.location = new system.drawing.point(8, 344);
   this.labeldown.name = "labeldown";
   this.labeldown.size = new system.drawing.size(88, 23);
   this.labeldown.tabindex = 4;
   this.labeldown.text = "s(down) 向下";
   this.labeldown.textalign = system.drawing.contentalignment.middleright;
   //
   // labelup
   //
   this.labelup.forecolor = system.drawing.color.white;
   this.labelup.location = new system.drawing.point(8, 312);
   this.labelup.name = "labelup";
   this.labelup.size = new system.drawing.size(88, 23);
   this.labelup.tabindex = 3;
   this.labelup.text = "w(up)   向上";
   this.labelup.textalign = system.drawing.contentalignment.middleright;
   //
   // labelgameintroduce
   //
   this.labelgameintroduce.font = new system.drawing.font("隸書", 12f, system.drawing.fontstyle.regular, system.drawing.graphicsunit.point, ((system.byte)(134)));
   this.labelgameintroduce.forecolor = system.drawing.color.white;
   this.labelgameintroduce.location = new system.drawing.point(8, 272);
   this.labelgameintroduce.name = "labelgameintroduce";
   this.labelgameintroduce.size = new system.drawing.size(88, 32);
   this.labelgameintroduce.tabindex = 2;
   this.labelgameintroduce.text = "游戲說明:";
   this.labelgameintroduce.textalign = system.drawing.contentalignment.middleleft;
   //
   // labelgamecurrentdifficulty
   //
   this.labelgamecurrentdifficulty.forecolor = system.drawing.color.white;
   this.labelgamecurrentdifficulty.location = new system.drawing.point(8, 48);
   this.labelgamecurrentdifficulty.name = "labelgamecurrentdifficulty";
   this.labelgamecurrentdifficulty.size = new system.drawing.size(88, 23);
   this.labelgamecurrentdifficulty.tabindex = 1;
   this.labelgamecurrentdifficulty.text = "一般";
   this.labelgamecurrentdifficulty.textalign = system.drawing.contentalignment.middleright;
   //
   // labelgamedifficulty
   //
   this.labelgamedifficulty.font = new system.drawing.font("隸書", 12f, system.drawing.fontstyle.regular, system.drawing.graphicsunit.point, ((system.byte)(134)));
   this.labelgamedifficulty.forecolor = system.drawing.color.white;
   this.labelgamedifficulty.location = new system.drawing.point(8, 8);
   this.labelgamedifficulty.name = "labelgamedifficulty";
   this.labelgamedifficulty.size = new system.drawing.size(88, 32);
   this.labelgamedifficulty.tabindex = 0;
   this.labelgamedifficulty.text = "游戲難度:";
   this.labelgamedifficulty.textalign = system.drawing.contentalignment.middleleft;
   //
   // formmain
   //
   this.autoscalebasesize = new system.drawing.size(6, 14);
   this.backcolor = system.drawing.color.black;
   this.clientsize = new system.drawing.size(632, 565);
   this.controlbox = false;
   this.controls.add(this.panel1);
   this.controls.add(this.panelgameregion);
   this.menu = this.menumain;
   this.name = "formmain";
   this.startposition = system.windows.forms.formstartposition.centerscreen;
   this.text = "貪吃蛇 - by lzumcj";
   this.windowstate = system.windows.forms.formwindowstate.maximized;
   this.keydown += new system.windows.forms.keyeventhandler(this.formmain_keydown);
   this.panel1.resumelayout(false);
   this.resumelayout(false);

  }
  #endregion

  ///
  /// 應用程序的主入口點。
  ///
  [stathread]
  static void main()
  {
   application.run(new formmain());
  }

  ///
  /// 選擇開始游戲
  ///
  ///
  ///
  private void menugamebegin_click(object sender, system.eventargs e)
  {
   this.menugamebegin.enabled = false;
   this.menugamerebegin.enabled = true;

   begingame();
  }

  ///
  /// 選擇重新開始游戲
  ///
  ///
  ///
  private void menugamerebegin_click(object sender, system.eventargs e)
  {
   begingame();
  }

  ///
  /// 選擇結束游戲
  ///
  ///
  ///
  private void menugameend_click(object sender, system.eventargs e)
  {
   exitgame();
  }

  ///
  /// 選擇游戲難度
  ///
  ///
  ///
  private void menuoptiongamedifficultyeasy_click(object sender, system.eventargs e)
  {
   selectgamedifficulty(sender , e);
  }

  private void menuoptiongamedifficultycommon_click(object sender, system.eventargs e)
  {
   selectgamedifficulty(sender , e);
  }

  private void menuoptiongamedifficultydifficult_click(object sender, system.eventargs e)
  {
   selectgamedifficulty(sender , e);
  }

  ///
  /// 選擇總在最前面
  ///
  ///
  ///
  private void menuoptiontopmost_click(object sender, system.eventargs e)
  {
   menuoptiontopmost.checked = !menuoptiontopmost.checked;
   this.topmost = menuoptiontopmost.checked;
  }

  ///
  /// 響應鍵盤輸入
  ///
  ///
  ///
  private void formmain_keydown(object sender, system.windows.forms.keyeventargs e)
  {
   //
   // 根據鍵盤輸入重新設置蛇的運動方向
   //
   if (snake != null)
    snake.resetmovedirection(e.keydata.tostring());
  }

  ///
  /// 開始游戲（設置游戲規則）
  ///
  private void begingame()
  {
   int igreencount = 0;  // 吃的綠色數

   // 清除上次剩下的食物
   if (snakefood != null)
   {
    snakefood.clear();
    snakefood.dispose();
   }
   snakefood = new snakefood(this.panelgameregion , imaxcount , iradius);

   // 清除上次的蛇
   if (snake != null)
   {
    snake.clear();
    snake.dispose();
   }

   // 初始化新蛇
   snake = new snake(this.panelgameregion , icount , iradius);
   snake.draw();

   int k = 0;
   while (!gameover())
   {
    application.doevents();
    snake.movenext();

    for (int iindex=0; iindex    {
     if (snakefood[iindex].centerx == snake.currentheadx && snakefood[iindex].centery == snake.currentheady)
     {
      if (snakefood[iindex].colornode == color.green)
      {
       snake.addtrail();

       igreencount++;
       snakefood.removefood(iindex);
      }
     }
    }

    // 統計結果
    labelinitcount.text = "初始蛇長:" + convert.tostring(icount);
    labelcurrentcount.text = "現在蛇長:" + convert.tostring(snake.count);
    labeleatgreencount.text = "吃了:● × " + convert.tostring(igreencount);
    labelscore.text = "得分:" + convert.tostring(igreencount * 20);

    // 兩次移動的時間間隔（即移動速度）
    thread.sleep(ispeed);

    // 顯示隨機產生的點 , 且控制當前最多只能有imaxcount
    if (k%(ispeed/40*30) == 0 && snakefood.currentcount    {
     snakefood.addfood();
    }
    k++;
   }

   this.menugamerebegin.enabled = true;

   dialogresult drresult = messagebox.show("重新開始游戲?" , "提示" , messageboxbuttons.okcancel , messageboxicon.information , messageboxdefaultbutton.button1);

   if (drresult == dialogresult.ok)
    begingame();
   else
    exitgame();
  }