Iterative and incremental model in Software Engineering - Step-by-Step Execution

Concept Flow - Iterative and incremental model

Start Project

↓

Plan Iteration 1

↓

Develop Increment 1

↓

Test Increment 1

↓

Review & Feedback

↓

Is Project Complete?

No→Plan Next Iteration

↓

Develop Increment 2

↓

Deliver Final Product

The model repeats cycles of planning, developing, testing, and reviewing small parts (increments) until the full product is complete.

Execution Sample

Software Engineering

Iteration 1: Plan -> Develop -> Test -> Review
Iteration 2: Plan -> Develop -> Test -> Review
...
Repeat until complete

Shows how each iteration plans, builds, tests, and reviews a small part of the project.

Analysis Table

Iteration	Phase	Action	Output	Next Step
1	Plan	Define goals for first increment	Plan document for increment 1	Develop
1	Develop	Build first increment features	Working increment 1	Test
1	Test	Test increment 1 features	Test results and bug list	Review
1	Review	Gather feedback and decide next steps	Feedback report	Is project complete? No
2	Plan	Define goals for second increment	Plan document for increment 2	Develop
2	Develop	Build second increment features	Working increment 2	Test
2	Test	Test increment 2 features	Test results and bug list	Review
2	Review	Gather feedback and decide next steps	Feedback report	Is project complete? Yes
-	-	-	-	Deliver final product

💡 Project complete after iteration 2, final product delivered.

State Tracker

Variable	Start	After Iteration 1	After Iteration 2	Final
Plan Document	None	Plan for increment 1	Plan for increment 2	Complete plan
Working Increment	None	Increment 1 built	Increment 2 built	Full product built
Test Results	None	Tested increment 1	Tested increment 2	All increments tested
Feedback	None	Feedback after iteration 1	Feedback after iteration 2	Final feedback incorporated

Key Insights - 3 Insights

Why do we repeat planning in each iteration instead of planning everything at once?

Because each iteration focuses on a small part, planning is done incrementally to adapt to feedback and changes, as shown in the execution_table rows for 'Plan' phase in each iteration.

How does testing after each increment help the project?

Testing early and often finds problems sooner, making fixes easier and improving quality, as seen in the 'Test' phase outputs in the execution_table.

What happens if the project is not complete after an iteration?

The model loops back to plan the next increment, continuing development until all parts are done, shown by the 'Is project complete? No' decision leading back to planning.

Visual Quiz - 3 Questions

Look at the execution_table, what is the output after the 'Develop' phase in iteration 1?

A Working increment 1

B Plan document for increment 1

C Test results and bug list

D Feedback report

💡 Hint

Check the row where Iteration is 1 and Phase is 'Develop' in the execution_table.

At which iteration does the project become complete according to the execution_table?

A Iteration 1

B Iteration 2

C Iteration 3

D Never

💡 Hint

Look at the 'Review' phase rows and the 'Is project complete?' column in the execution_table.

If feedback after iteration 1 was ignored, how would the variable 'Feedback' change in variable_tracker?

A It would still show 'Feedback after iteration 1'

B It would jump directly to 'Final feedback incorporated'

C It would remain 'None' after iteration 1

D It would be empty after iteration 2

💡 Hint

Check how 'Feedback' changes after each iteration in variable_tracker.

Concept Snapshot

Iterative and Incremental Model:
- Develop software in small parts called increments.
- Each iteration includes planning, development, testing, and review.
- Feedback after each iteration guides next steps.
- Repeat until the full product is complete.
- Helps manage risks and adapt to changes early.

Full Transcript

The Iterative and Incremental Model breaks down software development into repeated cycles called iterations. Each iteration plans, builds, tests, and reviews a small part of the project called an increment. After each iteration, feedback is gathered to improve the next increment. This cycle repeats until the entire product is complete. This approach helps catch problems early, adapt to changes, and deliver working software faster. The execution table shows each phase per iteration and the outputs produced. Variables like plan documents, working increments, test results, and feedback evolve step-by-step through the iterations. Key moments include understanding why planning repeats, the importance of testing each increment, and how the model loops until completion. The visual quiz tests understanding of outputs at each phase, when the project completes, and the role of feedback. Overall, this model supports flexible and manageable software development.