PHP implementation of the addition and subtraction verification code

  This article mainly introduces the PHP implementation of the addition and subtraction verification code code, you can use the addition and subtraction within 10 to generate pictures, the need for friends can refer to the following

  Code is as follows: <?php/* Picture Verification code file, add and subtract calculation mode/  class imagecode{   private $Jiashu  = 0     &NB Sp  //addends or meiotic  private $JianShu = 0;        //summand or  private $YunSuan = ';      //operator  private $DeShu   = 0;        // private $String  = ';      //String style  private $Img;                //Picture object  private $Width   = 100;      //picture width  private $Height  = 50;      //Picture height  private $Ttf     = ' num.ttf ';//font file  private $Session = ' code ';  //session variable    private function Jiashu () {  header (' content-type:image/png ');   $this-> Ji Ashu  = rand (1, 10);   $this-> Jianshu = rand (1, 10);   $this-> yunsuan= $this-> jiashu > $this-> jianshu? '-' : '+';   $this-> Deshu   = $this; Jiashu > $this-> jianshu? $this-> jiashu-$this-> jianshu: $this-> Jiashu + $this-> Jianshu; &NBSP}    public function show ($W = $H = +, $T = ' Num.ttf ', $Code = ' Code ') {  $this-> Jiashu ( );   $this-> String = $this-> Jiashu. $this-> Yunsuan. $this-> Jianshu. '= ? ';   $this-> Width  = $W;   $this-> Height = $H;   $this-> Ttf    = $T;   $this-> session= $Code;   Session_Start ();   $_session[$this-> Session] = $this-> Deshu;   $this-> Images (); &NBSP}    private function Images () {  $this-> Img = imagecreate ($this-> Width, $this-> Height );   $background _color = imagecolorallocate ($this-> Img, 255, 255, 255);   Imagecolortransparent ($this-> Img, $background _color);         imagettftext ($this-> img, 0, 1, imagecolorallocate ($this-> img, 0, 0, 0), $th Is -> TTF, $this-> String);   $this-> echoimages (); &NBSP}    private function echoimages () {  imagepng ($this-> img);   Imagedestroy ($this-> img) ; &NBSP}  }   $ImageCode = new Imagecode; $ImageCode-> Show (130, the ' Num.ttf ', ' Code ');