149-PHP sensitive transfer function

? < PHP
     $ STR = '. The PHP IS A Very Good Programming Language';         // definition of a string 
    echo "unprocessed String: <br /> { $ STR }" ;
     // respectively using each function processing character and outputs the result of the processing sequence 
    $ STR = strtolower ( $ STR );
     echo "<br /> strtolower function converts a string using lowercase: <br /> { $ STR }" ;
     $ STR = ucfirst ( $ STR ) ;
     echo "<br /> ucfirst function to convert character string using the first letter is capitalized: <br /> { $ STR }" ;
    $str=ucwords($str);
    echo "is the first letter of each word string using ucwords <br /> function to convert to uppercase: <br /> { $ STR }" ;
     $ STR = strtoupper ( $ STR );
     echo "<br /> function using strtoupper convert a string to uppercase: <br /> { $ str } " ;
 >?