perl programming, homework help

To become familiar with Perl programs and to see how to interact with the operating system, write a Perl program that performs the following tasks:

Generate a menu to ask the user for the task that he or she would like to see performed.
The available tasks are as follows:
- Show current date and time.
- Show users currently logged in.
- Show the name of the working directory.
- Show the contents of the working directory.
Prompt the user for the choice, and perform the system command.

Also, describe how variables in Perl are handled, specifically with respect to the need for declaration and type casting.