Making the first letter of every sentence upper case using ucfirst

Question

I'm trying to make the first letter of every sentence to be upper case while keeping the punctuation marks. I have tried ucfirst, but it only makes the first letter of the string uppercase, and not every other sentences. How do I fix this?

$text = "yes. are you listening to me? huh?!"
$text = ucfirst($text);

echo $text;

Expected Output:

Yes. Are you listening to me? Huh?!"

Actual Output:

Yes. are you listening to me? huh?!"

Answer 1

Try this:

function ucfirstSentence($str){
     $str = ucfirst(strtolower($str));
     $str = preg_replace_callback('/([.!?])\s*(\w)/', 
       create_function('$matches', 'return strtoupper($matches[0]);'), $str);
     return $str;
}