62.String lowerCase & UpperCase.php

<?php

    $str = "hello world";

    $arr = strtoupper($str);

    echo $arr;

    echo "<br>";

    $str = "hello world";

    $arr = strtolower($str);

    echo $arr;

    echo "<br>";

    $str = "hello world";

    $arr = ucfirst($str);

    echo $arr;

    echo "<br>";

    $str = "hello world";

    $arr = lcfirst($str);

    echo $arr;

    echo "<br>";

    $str = "hello world";

    $arr = ucwords($str);

    echo $arr;

?>