A convenient way to find a free port is to pass in a null address, which automatically binds the socket to the local host address and USES a free ephemeral port.

For example, if email address is null or only contains Spaces, the message "Enter your email" will be shown when the form is validated.

Data type specification: the ability to tell the UI to display the data at a given address as a specific data type - for example, this address represents the start of a null-terminated string.