Use cases are generally a set of interaction between the User/Actor with the system to generate a desired output.
A use case diagram is a graphical representation of all use case that interacts with the system. Use case diagram is part of Unified Modelling language also known as UML.
Set of Use cases that are used in this ATM use case diagram to understand the requirements of the ATM are given below:
• Insert ATM card
• Enter pin
• Perform required transaction
o Change pin
Both customer and Bank are treated as actor. Actors are the one who interacts with the system.