Communication between drones in Drone Programming - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Message Passing Output

What is the output of this drone communication code snippet?

Drone Programming

drone1 = {'id': 101, 'message': 'Hello'}
drone2 = {'id': 102, 'message': ''}
# drone2 receives message from drone1
drone2['message'] = drone1['message']
print(drone2['message'])

A null

B Hello

C '' (empty string)

D Error: KeyError

💡 Hint

Think about how drone2 gets the message from drone1.

The code assigns drone1's message to drone2's message, so drone2 prints 'Hello'.

🧠 Conceptual

intermediate

Communication Protocol Concept

Which communication protocol is best suited for drones to exchange short messages quickly and reliably over short distances?

A Wi-Fi

B Satellite

C Bluetooth

D Fiber Optic Cable

💡 Hint

Think about short-range wireless communication.

Bluetooth is designed for short-range, quick, and reliable wireless communication, ideal for drones nearby.

🔧 Debug

advanced

Fix the Drone Message Broadcast Bug

What error does this code raise when drones try to broadcast messages to each other?

Drone Programming

drones = [{'id': 1, 'msg': 'Hi'}, {'id': 2, 'msg': ''}]
for drone in drones:
    for other in drones:
        if drone != other:
            other['msg'] = drone['msg']
print(drones[1]['msg'])

A TypeError: unsupported operand type(s)

B IndexError: list index out of range

C No error, output is 'Hi'

D KeyError: 'message'

💡 Hint

Check the dictionary keys used in the code.

The key 'message' does not exist; the correct key is 'msg', so KeyError occurs.

📝 Syntax

advanced

Identify the Syntax Error in Drone Communication Loop

Which option contains the syntax error preventing the drone communication loop from running?

Drone Programming

for drone in drones
    print(drone['id'])

A for drone in drones\n print(drone['id'])

B for drone in drones:\nprint(drone['id'])

C for drone in drones:\n print(drone['id'])

D for drone in drones: print(drone['id'])

💡 Hint

Look for missing punctuation in the for loop.

Option A is missing the colon ':' after the for statement, causing a syntax error.

🚀 Application

expert

Calculate Total Messages Exchanged

Given 4 drones where each drone sends a message to every other drone exactly once, how many total messages are exchanged?

A 12

B 16

C 8

D 6

💡 Hint

Each drone sends messages to all other drones except itself.

Each of the 4 drones sends messages to 3 others, so 4 * 3 = 12 messages total.

Practice

1. What is the main purpose of communication between drones in a fleet?

easy

A. To share important information and coordinate tasks

B. To recharge each other's batteries

C. To change their physical appearance

D. To compete for the strongest signal

Solution

1. Step 1: Understand drone communication purpose

   Drones communicate to share data and work together efficiently.

2. Step 2: Identify correct purpose from options

   Only To share important information and coordinate tasks mentions sharing information and coordination, which matches the purpose.

3. Final Answer:

   To share important information and coordinate tasks -> Option A

4. Quick Check:

   Communication = Share info and coordinate [OK]

Hint: Communication means sharing info, not physical changes [OK]

Common Mistakes:

• Thinking drones recharge each other
• Confusing communication with appearance changes
• Assuming drones compete instead of cooperate

2. Which of the following is the correct way to send a message from drone A to drone B in drone_programming?

easy

A. send_message(droneA, droneB, 'Hello')

B. droneB.receive_message(droneA.send_message('Hello'))

C. droneA.send_message('Hello').to(droneB)

D. droneA.message('Hello') -> droneB

Solution

1. Step 1: Understand message sending syntax

   In drone_programming, a drone sends a message by calling send_message, and the receiver uses receive_message.

2. Step 2: Check which option matches this syntax

   droneB.receive_message(droneA.send_message('Hello')) shows droneA sending and droneB receiving correctly.

3. Final Answer:

   <code>droneB.receive_message(droneA.send_message('Hello'))</code> -> Option B

4. Quick Check:

   Send then receive method call = droneB.receive_message(droneA.send_message('Hello')) [OK]

Hint: Send message from sender, receive on receiver drone [OK]

Common Mistakes:

• Using wrong method names
• Trying to chain send_message with .to()
• Incorrect function call order

3. What will be the output of this code snippet?

droneA.inbox = []
droneB.inbox = []
message = droneA.send_message('Status update')
droneB.receive_message(message)
print(droneB.inbox)

medium

A. ['Status update']

B. []

C. ['Status update', 'Status update']

D. Error: inbox attribute missing

Solution

1. Step 1: Trace message sending and receiving

   droneA sends 'Status update', droneB receives it and adds to inbox.

2. Step 2: Check droneB's inbox content after receiving

   Inbox contains one message: ['Status update'].

3. Final Answer:

   ['Status update'] -> Option A

4. Quick Check:

   Inbox after receive_message = ['Status update'] [OK]

Hint: Received messages go into inbox list [OK]

Common Mistakes:

• Assuming inbox stays empty
• Thinking message duplicates
• Expecting attribute errors

4. Identify the error in this drone communication code:

droneA.inbox = []
droneB.inbox = []
message = droneA.send_message('Ready')
droneB.receive_message(message)
print(droneA.inbox)

medium

A. print statement syntax is incorrect

B. send_message method is missing parentheses

C. receive_message should be called on droneA, not droneB

D. droneA.inbox is printed but droneA never received messages

Solution

1. Step 1: Analyze message flow

   droneA sends message, droneB receives it, so droneB's inbox changes, not droneA's.

2. Step 2: Check printed inbox

   Printing droneA.inbox shows empty because droneA did not receive any message.

3. Final Answer:

   droneA.inbox is printed but droneA never received messages -> Option D

4. Quick Check:

   Inbox printed is sender's, but sender has no received messages [OK]

Hint: Print inbox of receiver, not sender [OK]

Common Mistakes:

• Confusing sender and receiver inboxes
• Missing parentheses on method calls
• Wrong drone calling receive_message

5. You want to make sure droneC only processes messages from droneA and ignores others. Which code snippet correctly implements this filtering?

def process_inbox(droneC):
    for msg in droneC.inbox:
        if msg.sender_id == 'droneA':
            print(f"Processing: {msg.content}")
        else:
            print("Ignoring message")

hard

A. The else block should delete the message from inbox

B. The code should check msg.receiver_id instead of sender_id

C. The code correctly checks sender_id before processing messages

D. The for loop should iterate over droneA.inbox, not droneC.inbox

Solution

1. Step 1: Understand message filtering logic

   Filtering by sender_id ensures only messages from droneA are processed.

2. Step 2: Verify code matches filtering goal

   Code checks msg.sender_id == 'droneA' and processes accordingly, which is correct.

3. Final Answer:

   The code correctly checks sender_id before processing messages -> Option C

4. Quick Check:

   Filter by sender_id = correct filtering [OK]

Hint: Filter messages by sender_id to process only desired drones [OK]

Common Mistakes:

• Checking receiver_id instead of sender_id
• Trying to delete messages in else block unnecessarily
• Iterating wrong drone's inbox