根据变量值重定向到不同的页面[重复]

I am using Geoplugin to get visitor city and header to Redirect to different page according to it but I got

Warning: Cannot modify header information - headers already sent

and Its not redirecting any page

please help me to resolve this

Code I Tried:

<?php
  $user_ip = getenv('REMOTE_ADDR');
  $geo = unserialize(file_get_contents("http://www.geoplugin.net/php.gp?
  ip=$user_ip"));
  $city = $geo["geoplugin_city"];
  $region = $geo["geoplugin_regionName"];
  $country = $geo["geoplugin_countryName"];
  echo "City: ".$city."<br>";
  echo "Region: ".$region."<br>";
  echo "Country: ".$country."<br>";

 switch ($city) {
    case "Vijayawada":
      header("Location: http://www.website.com/test/andhra.php");
       break;
  case "Bangalore":
        header("Location: http://www.website.com/test/bglr.php");
        break;
  default:header("Location: http://www.website.com/test/index.php");
 exit;

} ?>

</div>

You are getting error because you are echoing these before header

  echo "City: ".$city."<br>";
  echo "Region: ".$region."<br>";
  echo "Country: ".$country."<br>";

There should not be any output before header