comparing strings, adding HTML tag to difference

[viveleroi0]

If I'm comparing two strings, how would I add a simple <b> tag to the differences?

For example:

this is string 1
this is amazing string number 2

when compared, I want it show:

this is <b>amazing</b> string <b>number 2</b>

[dalecosp]

Well, it's probably a kluge, but it was interesting for me:

<?php

$str="this is string one";
$str1="this is amazing string number one";

$arr1=array();
$arr2=array();
$diffs=array();

$tok=strtok($str, " ,.\t\n");
while ($tok!==false) {
   $arr1[]=$tok;
   $tok=strtok(" ,.\t\n");
}

$tok=strtok($str1," ,.\t\n");
while ($tok!==false) {
   $arr2[]=$tok;
   $tok=strtok(" ,.\t\n");
}

$diffs=array_diff($arr2,$arr1);

$ct=0;
foreach($arr2 as $a) {
  if(in_array($a, $diffs)) {
    $arr2[$ct]="<b>".$a."</b>";
   }
   $ct++;
}

echo implode($arr2, " ");

?>

HTH,