[X337]

Код:

if(!sscanf(inputtext, "{s[256]'@'s[256]'.'s[256]}")) 
{
	// the email is valid depends on those patterns...
}

Or you can write a function to make it easier to use if you want to call it multiple times.

Код:

IsValidEmail(text[]) // It will return true if text[] is a valid email, it will return false otherwise.
{
	return !sscanf(text, "{s[256]'@'s[256]'.'s[256]}");
}