01 / Specify
Known drinks only; whole positive quantities; prices in cents; unknown or invalid orders receive a clear message.
Teach Python
Prepared input / stdin
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OUTPUT
Predict first · reveal original output
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Quick self-check
Reveal explanation
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Cafe project brief & object design
PRACTISE INDEPENDENTLY
Your next build: the Latte Cafe order desk.
Combine the ideas in your own version. The lab runs each example independently; combine the required pieces explicitly instead of relying on variables or files from earlier runs.
02 / Build in small steps
Start from the receipt example. Extract a calculation function, add validation, then save and reload the order as CSV or JSON.
03 / Review the evidence
Check two lattes plus one tea total 1200 cents, an empty order totals zero, and invalid quantities are rejected. Explain why each check exists.
In one-to-one online sessions, we can review your trace, debugging decisions and explanation, then choose the next exercise. These are studio-authored examples; UOW’s public subject descriptions inform topic coverage, not university affiliation or official assessment preparation.
OOA → OOD → OOPOOA OOD OOP
Design the cafe before adding classes.
The same cafe story connects requirements, responsibilities and Python objects. The class starter is deliberately small; quantity validation is a follow-up exercise.
Understand the order
Name the drinks, prices, quantities and output. Decide how an empty order and an invalid quantity should behave before choosing classes.
Assign responsibilities
MenuItem owns its name and unit price. Order owns its lines and total. An order contains menu items through composition, rather than inheriting from an item.
Implement and check
Run “Model a cafe order”. Create separate orders, inspect their state and add validation. Check two lattes total 900 cents and an empty order totals zero.
MenuItem
name · price_centsOrder
lines[] · add(item, quantity)
total_cents()self refers to an instance. Each Order creates its own lines list in __init__; a mutable class-level list would be shared across orders.