When writing an error prompt, should we end the sentence with a exclamation mark or a dot?
I am writing an application for iPhone and I have some error prompt in my application like "Your password must be 8 character long with alphanumeric characters!" However, I am not completely sold on the idea of putting an exclamation mark (!) on error prompt. Are there situation where it might be warranted, and what about just replacing exclamation marks with dots? Is there a sort of standard among programmers?