Complete for freeIntermediateBrowser simulator included

Course 5

Object-Oriented Python and Software Design

Design maintainable Python software with classes, composition, interfaces, type hints, custom errors, modules, tests, and deliberate refactoring. The course combines structured lessons, guided browser concept simulations, and learner-created project files made with freely installable or open tools described in the course instructions. This guided page does not execute code, train models, run databases, create repositories, access hardware, or provide hosted infrastructure.

Free completion promise: The always-free pathway combines guided design simulations with learner-created Python and test files made in freely installable or open tools. The C4T page does not run an IDE or tests.

Before you begin

Requirements & setup for Object-Oriented Python and Software Design

Start with the complete free pathway below. Hardware, subscriptions, paid APIs, and cloud credits are never required.

Start here · free path

Your complete $0 setup

The always-free pathway combines guided design simulations with learner-created Python and test files made in freely installable or open tools. The C4T page does not run an IDE or tests.

$0 required

Setup checklist

0 of 6 complete

This checklist is a temporary setup aid and resets when the page reloads. Saved course progress begins in the setup lessons below.

1. Choose the free learning path
Use the browser-based tools and simulations throughout this course. Paid software, APIs, cloud credits, GPUs, and physical equipment are optional.
About 2 min
2. Set up C4T Python Design Concept Simulator
Open the concept simulator and read its scenario, assumptions, and limitations.
About 5 minOpen C4T Python Design Concept Simulator (opens in a new tab)
3. C4T Python Design Concept Simulator: step 2
Make a prediction, adjust the available controls, and compare the result with the explanation.
About 5 min
4. C4T Python Design Concept Simulator: step 3
Record what changed and why; repeat with at least one different input.
About 5 min
5. C4T Python Design Concept Simulator: step 4
For applied work, follow the course instructions to create and keep your own project files with a freely installable or open tool appropriate to the subject.
About 5 min
6. Run the setup check
C4T Python Design Concept Simulator: Complete one prediction-and-explanation cycle and record the evidence you would carry into a learner-created project file.
About 5 min

Software

1 item

C4T Python Design Concept Simulator

Course need

C4T Python Design Concept Simulator

Free

A free browser concept simulator with adjustable values, a prediction prompt, deterministic feedback, and a short explanatory trace. This guided page does not execute code, train models, run databases, create repositories, access hardware, or provide hosted infrastructure. Use keyboard controls and the text trace or written alternative when a visual or pointer interaction is not suitable.

Open the concept simulator and read its scenario, assumptions, and limitations.
Make a prediction, adjust the available controls, and compare the result with the explanation.
Record what changed and why; repeat with at least one different input.
For applied work, follow the course instructions to create and keep your own project files with a freely installable or open tool appropriate to the subject.

Open C4T Python Design Concept Simulator

Hardware

Nothing required

No physical hardware is needed for this course.

Accounts

Nothing required

No external account is needed for this course.

What you will be able to do

Learning outcomes

Model responsibilities with classes, objects, state, and constructors.
Choose composition or inheritance using explicit trade-offs.
Define typed interfaces and domain-specific exceptions.
Refactor a multi-module application with unit-test protection.

Included downloads

Free starter assets

Original · synthetic · licensed

These small files contain no personal data, credentials, or secrets. Dataset fixtures are CC0 and starter code is MIT licensed.

Starter pack guide & licensesSee what each original synthetic dataset, fixture, and starter file contains.Python project starterA small standard-library CSV application with clearly marked extension tasks.

Build real work

Assignments & capstone

Free tools accepted

Class design and relationship review

Model a small domain, submit a class diagram, and justify composition or inheritance for each relationship.

The always-free pathway combines guided design simulations with learner-created Python and test files made in freely installable or open tools. The C4T page does not run an IDE or tests. Submit a project file, text trace, screenshots with descriptions, or equivalent simulator evidence.

Test-protected modular refactor

Split a learner-created Python program into typed modules, add custom errors, and protect behavior with unit tests.

Final assessment

Object-oriented Python application

Build or refactor a substantial application using multiple classes, clear responsibilities, justified relationships, type hints, custom exceptions, modules, reusable components, tests, and a design document. Deliverables: Multi-module Python application, Class and responsibility diagram, Typed public interfaces, Custom exception strategy, and Passing unit tests and design rationale.

Prerequisites & pacing

Skills assumed

Collections, files, functions, validation, and Python project structure

Recommended prior courses

Python Projects and Problem Solving

These are advisory, not locks. If you already have the skills listed above, enroll directly.

Choose your pace

self paced: 10 weeks at 5 hours per week
weekly: 10 weeks at 5 hours per week

Part of this learning path

🧭 Coding Foundations · step 5 of 5
Start from zero and finish able to design, write, and debug real programs.

Course created by Zafir Shamsi.