OOP
Encapsulation means your object protects its own rules. Other code should ask the object to do a valid action, not reach inside and edit its state.
In a hackathon repo, recruiters do not expect a huge design. They look for code where bugs are harder to create.
If anyone can change every field, your class is just a loose data bag. A small method like markPaid() or assignDriver() can check rules before state changes.
0 of 7 lessons done · proved by a submitted project with a public repository
This looks simple, but any part of the app can put the order into a wrong state. You can mark it paid with zero amount. You can set any random status string.
class FoodOrder:
def __init__(self, order_id, total_rupees):
self.order_id = order_id
self.total_rupees = total_rupees
self.status = "CREATED"
self.paid = False
order = FoodOrder("ORD-17", 0)
order.paid = True
order.status = "DONE_DONE"Keep fields private by convention, then expose methods for real actions. This version is still small. No framework. No extra pattern.
class FoodOrder:
VALID_STATUSES = {"CREATED", "PAID", "CANCELLED"}
def __init__(self, order_id, total_rupees):
if total_rupees <= 0:
raise ValueError("Order total must be more than 0")
self._order_id = order_id
self._total_rupees = total_rupees
self._status = "CREATED"
def mark_paid(self):
if self._status == "CANCELLED":
raise ValueError("Cancelled order cannot be paid")
self._status = "PAID"
def cancel(self):
if self._status == "PAID":
raise ValueError("Paid order cannot be cancelled here")
self._status = "CANCELLED"
def summary(self):
return {
"order_id": self._order_id,
"total_rupees": self._total_rupees,
"status": self._status
}
order = FoodOrder("ORD-17", 199)
order.mark_paid()
print(order.summary())Do each one yourself, then tap it to tick it off. The ticks are only a checklist for you: they are not marked or scored.
0 of 5 done
Do not create getStatus() and setStatus() for every field by habit. That often gives public access with extra typing.
Use a setter only when outside code is allowed to change that value directly. If there is a rule, name the method after the action and enforce the rule there.
You can ask ChatGPT or Gemini: “Given this class, which fields should be private and what methods should change them?” Then check the answer yourself.
Reject suggestions that add abstract factories, managers, or service layers for a tiny feature. For this lesson, one clear class with protected rules is enough.
Do each one yourself, then tap it to tick it off. The ticks are only a checklist for you: they are not marked or scored.
0 of 5 done
Answer the quick check to finish this lesson.