Trying to access array offset on value of type int

Question

Recently I started using php v7.4 and got this error Trying to access array offset on value of type int

function getsize($size) {
    if ($size === null) return null;
    $last = strtolower($size{strlen($size)-1});
    $size = (int) $size;
    switch($last) {
        case 'g':
            $size *= 1024;
        case 'm':
            $size *= 1024;
        case 'k':
            $size *= 1024;
    }
    return $size;
}

how do I fix it :'(

Answer 1

no errors, just switched curly braces to brackets and it worked, (after setting $size = strlen($size); as Barno said)