我的链接没有正确显示没有等号php


my links are not showing correctly no equal sign php

当我在gmail或hotmail或任何其他邮件软件中打开邮件时,通过带有链接的邮件发送不显示等号或完整链接

$reg = new REGISTRATION();
$reg->email = rtrim($_POST["email"]);
$reg_email =  $reg->email;
$id =rtrim(md5($reg_email.time()));
$link="http://".$url."activate.php?token=$id&code=$code";

$to = $reg->email;
$subject = "Activate Profile";
$message = "Thank you for registering with us please click the link below to activate your account.'n'n".$link."'n'nLogin details'n'nUsername:$reg_email'nPassword:$reg_pass";
$headers = "From: "."registration@domain.com". PHP_EOL;
$headers .= "MIME-Version: 1.0" . PHP_EOL;
$headers .= "Content-type: text/plain; charset=utf-8" . PHP_EOL;
$headers .= "Content-Transfer-Encoding: quoted-printable" . PHP_EOL;

mail($to,$subject,$message,$headers);

在哪里定义$link中的$code ?

$reg = new REGISTRATION();
$reg->email = rtrim($_POST["email"]);
$reg_email =  $reg->email;
$id =rtrim(md5($reg_email.time()));
$code = YOUR_CODE_HERE;
$link="http://".$url."activate.php?token=".$id."&code=".$code;