Week 5 — Quiz (auto-graded) · Loops I: the `while` loop

Course: Introduction to Computer Science — CS1 / Programming Fundamentals in Python (CSCI 1101) · Silver Oak University (fictional sample) · Prof. Okafor
Objective tested: Objective 4 — while loops; counters & accumulators; predicting a loop's final value and iteration count; off-by-one (< vs <=); infinite-loop debugging; break.
Points: 10 (1 each) · Assignment group: Quizzes (10% of grade) · Due: end of Module 5.

This is the human-readable quiz with its vetted answer key and feedback. The import-ready Classic QTI is in F-quiz-week-05-qti.xml (generated by the shared validated script — parses with 10 items, every single-answer item exactly one correct). Execution gate: PASS — every final value, accumulator total, iteration count, and loop output keyed below was produced by actually running the code in Python, not hand-traced. (The infinite-loop item, Q4, is debugged by reading; the fixed version's output is run-verified.) The Canvas placement block is at the bottom of this file.

Blueprint

No trick questions; distractors are plausible mis-traces (off-by-one, counting the boundary wrong, ending value off by one, forgetting break fires).

Questions, key, and feedback

Q1 (MC). What does this program print?

count = 0
while count < 4:
    count = count + 1
print(count)

• A. 3
• B. 4 ✅
• C. 5
• D. nothing (it never stops)
  Feedback: The loop runs while count < 4, adding 1 each pass: 0→1→2→3→4. When count reaches 4, 4 < 4 is False, so it stops, and print shows 4. (A 3 is the off-by-one of stopping one early; the loop does terminate, so D is wrong. Run-verified: 4.)

Q2 (MC). What does this program print?

i = 2
while i < 10:
    print(i)
    i = i + 2

• A. 2 4 6 8 10 (each on its own line)
• B. 2 4 6 8 (each on its own line) ✅
• C. 2 3 4 5 6 7 8 9
• D. 2 4 6 8 10 12
  Feedback: Starting at 2 and stepping by 2 while i < 10: it prints 2, 4, 6, 8. When i becomes 10, 10 < 10 is False, so 10 is not printed (< excludes the boundary). (A includes 10 — the off-by-one. C steps by 1. Run-verified: 2 4 6 8.)

Q3 (MC). This loop adds up the numbers 1 through 6. What does it print?

total = 0
n = 1
while n <= 6:
    total = total + n
    n = n + 1
print(total)

• A. 15
• B. 21 ✅
• C. 6
• D. 28
  Feedback: The accumulator builds 1+2+3+4+5+6 = 21. total starts at 0; each pass adds the current n (1 through 6, because <= 6 includes 6). (A 15 is the sum 1..5 — off by one. D 28 is 1..7. Run-verified: 21.)

Q4 (MC). This program is supposed to print 1, 2, 3, 4 but it never stops:

count = 1
while count < 5:
    print(count)

Why does it never stop, and what single line fixes it?
- A. The condition should be count <= 5; change < to <=
- B. The counter is never updated, so count < 5 stays True forever; add count = count + 1 inside the loop ✅
- C. while loops always run forever; use if instead
- D. The print is indented wrong; move it outside the loop
Feedback: This is an infinite loop — the classic missing STEP. Because count never changes, count < 5 is always True, so it prints 1 endlessly. The fix is to update the counter inside the body: add count = count + 1. (If one ever runs for real, press Ctrl+C or Stop to interrupt it.) Changing the condition (A) doesn't help — it'd still never update count. With the fix, it prints 1 2 3 4 — run-verified.

Q5 (Multiple answer — select all that apply). Which of the following statements are true?
- A. A while loop repeats its body as long as its condition is True ✅
- B. An accumulator should be initialized (e.g., total = 0) before the loop ✅
- C. A while loop always runs exactly once
- D. Forgetting to update the counter inside the loop can cause an infinite loop ✅
- E. while i < 5 and while i <= 5 always run the same number of times
Feedback: A while loop repeats while its condition holds (A); accumulators start before the loop (B); a missing counter update causes an infinite loop (D). C is false — a while loop can run zero, one, or many times depending on the condition. E is false — <= 5 runs one more iteration than < 5 (the off-by-one).

Q6 (Matching). Match each loop snippet to the value it prints (every pairing is run-verified).
| Loop snippet | Prints |
|---|---|
| c = 0 / while c < 3: / c += 1 / print(c) | 3 |
| t = 0 / i = 1 / while i <= 3: / t += i / i += 1 / print(t) | 6 |
| i = 0 / while i < 6: / i += 2 / print(i) | 6 (the loop variable's final value) |
| n = 4 / last = 0 / while n > 0: / last = n / n -= 1 / print(last) | 1 |
Feedback: (1) counts 0→3, prints 3. (2) accumulates 1+2+3 = 6. (3) steps 0→2→4→6; at 6, 6 < 6 is False, so it stops with i = 6. (4) counts down 4,3,2,1, remembering the last value seen, which is 1. (Two snippets print 6 for different reasons — a counter's end value vs. an accumulator's total — which is the point.)

Q7 (MC). You want a loop that prints the numbers 1, 2, 3, 4, 5 (including 5). Each option starts with i = 1, prints i, then does i = i + 1. Which condition is correct?

i = 1
while CONDITION:
    print(i)
    i = i + 1

• A. while i < 5:
• B. while i <= 5: ✅
• C. while i > 5:
• D. while i < 4:
  Feedback: while i <= 5 includes 5, so it prints 1 through 5. A while i < 5 stops at 4 — that's the off-by-one that silently drops the 5. while i > 5 is False immediately (prints nothing); while i < 4 prints only 1–3. (Run-verified: i <= 5 prints 1 2 3 4 5.)

Q8 (True / False). "After this loop runs, count is 5."

count = 1
while count <= 5:
    count = count + 1

• True
• False ✅
  Feedback: False. count ends at 6, not 5. The loop adds 1 and then re-checks the condition: when count is 5, 5 <= 5 is True, so it runs once more and steps to 6; then 6 <= 5 is False and it stops. The counter always ends one past the boundary. (Run-verified: printing count after the loop shows 6.)

Q9 (MC). How many times does the body of this loop run (how many lines does it print)?

i = 0
while i <= 10:
    print(i)
    i = i + 2

• A. 5 times
• B. 6 times ✅
• C. 10 times
• D. 11 times
  Feedback: It prints 0, 2, 4, 6, 8, 10 — that's 6 values (<= 10 includes 10). Then i becomes 12 and 12 <= 10 is False, so it stops. (A 5 forgets to count 0; D 11 counts every integer. Run-verified: 6 lines.)

Q10 (MC). What does this program print?

n = 1
while True:
    if n * n > 50:
        print(n)
        break
    n = n + 1

• A. nothing (it runs forever)
• B. 7
• C. 8 ✅
• D. 50
  Feedback: while True looks infinite, but the break ends it. The loop steps n upward and stops the first time n * n > 50: 7×7 = 49 is not over 50, but 8×8 = 64 is, so it prints 8 and breaks. (B 7 forgets that 49 isn't over 50; A forgets the break is the STOP. Run-verified: 8.)

Answer key (quick reference)

Quality gate (self-checked): each single-answer item has exactly one correct option; the multiple-answer item keys A, B, D (and requires C and E unselected); the matching item pairs four loops to their run-verified printed values (with two pairs legitimately equal to 6). Execution gate: PASS — the keys for the predict/accumulator/iteration items (Q1 4; Q2 2 4 6 8; Q3 21; Q6 3/6/6/1; Q9 6 lines; Q10 8) and the off-by-one items (Q7, Q8 count ends 6) were each produced by running the code in Python, not hand-traced. The infinite-loop item (Q4) is diagnosed by reading the buggy code; its fixed form (1 2 3 4) is run-verified. Distractors are plausible mis-traces (Q2 2 4 6 8 10 = including the boundary; Q3 15 = summing 1..5; Q8 5 = forgetting the step-then-recheck).

Item-bank entries (for variants + the midterm/final)

All ten items are tagged course=CSCI1101 · week=5 · objective=4 · topic=while-loops-counters-accumulators and deposited in Item Bank: Week 5 — Loops I (while). The midterm (Week 8) and the per-term variant updates draw fresh items from this bank. (Tags: q1 final-value, q2 predict-step2, q3 accumulator-sum, q4 infinite-loop-debug, q5 true-statements, q6 snippet-match, q7 off-by-one, q8 ends-one-past, q9 iteration-count, q10 break.)

Canvas placement block

canvas_object   = Quizzes::Quiz
title           = "Week 5 Quiz — Loops I: the while loop"
assignment_group = "Quizzes"
points_possible = 10
grading_type    = points
due_offset_days = 5        # 5 days after module start (Sun Oct 4)
published       = true
shuffle_answers = true
ai_permitted    = false    # AI is not permitted on quizzes
provenance      = "~ Prof. Okafor's edition · Fall 2026 · built with thecoursemaker.com"