A local bank intends to install a new automated teller machine (ATM) to allow users (i.e., bank customers) to perform basic financial transactions (Fig. 22.1). Each user can have only one account at the bank. ATM users should be able to view their account balance, withdraw cash (i.e., take money out of an account) and deposit funds (i.e., place money into an account).
The user interface of the automated teller machine contains the following hardware components:
• a screen that displays messages to the user
• a keypad that receives numeric input from the user
• a cash dispenser ...