help parsing user input

[Anon]

I would like to check the user input of a username field so that it must start with a letter and be only 20 characters in length.

How do I check the first character is a letter?

Thanx in advance,

Ben.

[Anon]

if((($username[0] >= "a" && $username[0] <= "z") || )$username[0] >= "A" && $username[0] <= "Z")) && (strlen($username) <= 20))
{
echo"Username ok";
}

[Anon]

...or

if(
preg_match("^{[A-Za-z].{19}",$username)}
)
{...}