Popcorn Hack 1

Prediction: When the amount is 0, it will print “The requested amount is normal or zero.” When changed to an amount over 100, it will print “This message is asking for a large amount of money.”

Code Runner Challenge

3.6 Popcorn 1 - Run it first. Then make both outcomes print.

View IPYNB Source 
# CODE_RUNNER: 3.6 Popcorn 1 - Run it first. Then make both outcomes print.
amount_requested = 0

# 1 condition -> 2 outcomes -> 2 answers
if amount_requested > 100:
    print("This message is asking for a large amount of money.")
else:
    print("The requested amount is normal or zero.")
Lines: 1 Characters: 0
Output
Click "Run" in code control panel to see output ...

Code Runner Challenge

3.6 Popcorn 1 - test the other outcome

View IPYNB Source 
# CODE_RUNNER: 3.6 Popcorn 1 - test the other outcome
amount_requested = 150 
if amount_requested > 100:
    print("This message is asking for a large amount of money.")
else:
    print("The requested amount is normal or zero.")
Lines: 1 Characters: 0
Output
Click "Run" in code control panel to see output ...

Actual output:

  • The requested amount is normal or zero.
  • This message is asking for a large amount of money.

Popcorn Hack 2

Prediction: Since the risk_score is exactly 9, it will trigger the first condition (>= 9) and print the scam warning.

Code Runner Challenge

3.6 Popcorn 2 - fixed order, highest threshold first

View IPYNB Source 
# CODE_RUNNER: 3.6 Popcorn 2 - fixed order, highest threshold first
risk_score = 9

if risk_score >= 9:
    print("Do not reply. This is almost certainly a scam.")
elif risk_score >= 6:
    print("This looks risky. Check with someone you trust before replying.")
elif risk_score >= 3:
    print("Be a little careful, but this is probably fine.")
else:
    print("Nothing suspicious in this message.")
Lines: 1 Characters: 0
Output
Click "Run" in code control panel to see output ...

Actual output:

  • Do not reply. This is almost certainly a scam.

Original (broken) order: with risk_score = 9, the buggy chain checked >= 3 first, so it printed “Be a little careful, but this is probably fine.” That’s dangerously wrong for the worst possible score.

Unreachable branches in the original: elif risk_score >= 6 and elif risk_score >= 9. Any score that is 6 or higher (or 9 or higher) is also >= 3, so the first if always catches it, and those two branches can never run for any score. The fix is to order thresholds highest first: >= 9, then >= 6, then >= 3, then else.

Homework

Prediction:

  • “gift card” is in the message (+4)
  • amount is 500 which is > 100 (+3)
  • contact is not known (+2) Total risk score is 9. It will print the extreme risk warning.

Code Runner Challenge

3.6 Homework - score a message, then advise on it

View IPYNB Source 
# CODE_RUNNER: 3.6 Homework - score a message, then advise on it

message = "URGENT: send gift cards now to unlock your account"
amount_requested = 500
known_contact = False

risk_score = 0

# TODO 1: add to risk_score using conditionals, one signal at a time
# These do not need an else statement because if a signal isn't present, 
# we simply want to do nothing and leave the score exactly as it is.
if "gift card" in message:
    risk_score += 4

if amount_requested > 100:
    risk_score += 3

if not known_contact:
    risk_score += 2

# TODO 3: count comment in this form, with your real numbers:
# 3 thresholds -> 4 outcomes -> 4 answers

# TODO 2: report on the final score with an if / elif / else chain
if risk_score >= 9:
    print("Do not engage. This is an extreme risk and likely a scam.")
elif risk_score >= 6:
    print("High risk. Verify this person's identity before doing anything.")
elif risk_score >= 3:
    print("Moderate risk. Be cautious and look out for other red flags.")
else:
    print("Low risk. Proceed normally, but stay alert.")
Lines: 1 Characters: 0
Output
Click "Run" in code control panel to see output ...

Actual output:

  • Do not engage. This is an extreme risk and likely a scam.

Code Runner Challenge

3.6 Homework - reachability and extreme tests

View IPYNB Source 
# CODE_RUNNER: 3.6 Homework - reachability and extreme tests
def score_and_advise(message, amount_requested, known_contact):
    risk_score = 0
    if "gift card" in message:
        risk_score += 4
    if amount_requested > 100:
        risk_score += 3
    if not known_contact:
        risk_score += 2

    # 3 thresholds -> 4 outcomes -> 4 answers
    print("Score:", risk_score)
    if risk_score >= 9:
        print("Do not engage. This is an extreme risk and likely a scam.")
    elif risk_score >= 6:
        print("High risk. Verify this person's identity before doing anything.")
    elif risk_score >= 3:
        print("Moderate risk. Be cautious and look out for other red flags.")
    else:
        print("Low risk. Proceed normally, but stay alert.")

# Extreme test: every signal tripped
score_and_advise("URGENT: send gift cards now to unlock your account", 500, False)
# High-risk branch: gift card + stranger, small amount
score_and_advise("Can you buy me a gift card?", 50, False)
# Moderate branch: large amount from a known contact
score_and_advise("Can you lend me money for rent?", 300, True)
# Extreme test: completely clean message
score_and_advise("Hi Mom, are we still on for Sunday?", 0, True)
Lines: 1 Characters: 0
Output
Click "Run" in code control panel to see output ...

Reachability Proof

Branch Inputs (message / amount / known_contact) Score Output
>= 9 “…send gift cards now…” / 500 / False 4+3+2 = 9 Do not engage…
>= 6 “Can you buy me a gift card?” / 50 / False 4+2 = 6 High risk…
>= 3 “Can you lend me money for rent?” / 300 / True 3 Moderate risk…
else “Hi Mom, are we still on for Sunday?” / 0 / True 0 Low risk…

Every branch has an input that reaches it, so there is no dead code. Extreme tests: the clean message (score 0) and the all-signals message (score 9) both print a sensible answer.