[Solved] Identify the bug in this order tracking state machine snippet:state = 'shipped' event = 'cancel_order' if state == 'placed' and event == 'cancel_order':... | LLD

LLD - Design — Food Delivery System

Identify the bug in this order tracking state machine snippet:

state = 'shipped'
event = 'cancel_order'
if state == 'placed' and event == 'cancel_order':
    state = 'cancelled'
elif state == 'shipped' and event == 'cancel_order':
    print('Cannot cancel after shipping')
else:
    state = 'cancelled'
print(state)

AThe else block cancels order even after shipping

BMissing transition from 'placed' to 'shipped'

CNo print statement for cancellation confirmation

DState variable is not updated correctly for 'placed' state

Step-by-Step Solution

Solution:

Step 1: Analyze conditions for state 'shipped' and event 'cancel_order'
The if does not match. The elif matches, prints 'Cannot cancel after shipping' but leaves state unchanged. However, if event were different (e.g., 'deliver_order') with state='shipped', if and elif fail, else wrongly sets state='cancelled'.
Step 2: Identify why this is a bug
The else acts as a catch-all, allowing cancellation of shipped orders for unhandled events, contradicting the intent to prevent cancellation after shipping.
Final Answer:
The else block cancels order even after shipping -> Option A
Quick Check:
Else wrongly cancels unhandled shipped cases [OK]

Quick Trick: Else block can override specific conditions--check carefully [OK]

Common Mistakes:

Ignoring else block effects
Assuming print prevents state change
Not testing all branches

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Identify the bug in this order tracking state machine snippet:

Step 1: Analyze conditions for state 'shipped' and event 'cancel_order'

Step 2: Identify why this is a bug

Final Answer:

Quick Check:

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