Design technique 2 – use cases

Use cases are a systematic way of defining the interactions between actors and the software system to achieve a particular goal. It follows a set method of describing how your software will be used.

This concept is best explained with the use diagram of a real-life scenario; in this case, how an ATM machine is used.

Case study – how a bank's ATM is used

There are four common uses and interactions with the bank by a customer to complete the transaction. They are as follows:

• Check balance
• Deposit funds
• Withdraw cash
• Transfer funds

There are also two legitimate uses by a technician, who also interacts with the bank, to achieve their goal of fixing the ATM:

• Maintenance
• Repair

Figure...