Activity diagrams in Software Engineering - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an activity diagram?

An activity diagram is a visual representation that shows the flow of activities or actions in a system or process. It helps to understand how tasks are performed step-by-step.

beginner

Which symbol represents the start of an activity in an activity diagram?

A filled black circle (●) represents the start (initial node) of an activity in an activity diagram.

beginner

What does a diamond shape represent in an activity diagram?

A diamond shape represents a decision point where the flow can branch based on conditions.

intermediate

How do activity diagrams help in software development?

They help by showing the sequence of actions, decision points, and parallel processes, making it easier to understand, communicate, and design workflows.

intermediate

What is the difference between an activity and an action in an activity diagram?

An activity is a larger task that can contain multiple actions, while an action is a single step or operation within an activity.

What symbol marks the end of an activity diagram?

A A filled black circle

B A rectangle

C A diamond shape

D A circle with a border and a smaller filled circle inside

The end of an activity diagram is shown by a circle with a border and a smaller filled circle inside, called the final node.

Which element shows parallel activities happening at the same time?

A Initial node (filled circle)

B Decision node (diamond)

C Fork node (thick horizontal or vertical bar)

D Merge node (diamond)

A fork node splits the flow into multiple parallel paths, showing activities happening simultaneously.

What does a transition arrow represent in an activity diagram?

A The flow from one activity or action to another

B A decision point

C The start of the process

D An object or data

Transition arrows show the flow or movement from one activity or action to the next.

In activity diagrams, what is the purpose of a merge node?

A To combine multiple flows into one

B To split one flow into multiple flows

C To start the activity

D To end the activity

A merge node combines multiple alternative flows back into a single flow.

Which of the following is NOT typically shown in an activity diagram?

A Decision points

B Class attributes

C Sequence of actions

D Parallel processes

Class attributes belong to class diagrams, not activity diagrams.

Explain the main components of an activity diagram and their roles.

Think about how the diagram shows start, steps, choices, parallel tasks, and end.

Describe how activity diagrams can be used to improve understanding of a software process.

Consider how seeing the steps visually helps everyone involved.