AP CSP 3.6 Exercise 2: Conditionals Applied Challenge

Big Idea 3: Algorithms and Programming · Topic 3.6 · Exercise 2

Conditionals: Applied Challenge

Six traces where the branch taken depends on a boundary value.

Back to the Topic 3.6 lessonAll Big Idea 3 topics

How this one is different

Boundary values are where conditionals break and where the exam aims. Every question here puts a value on or next to a boundary.

Applied Practice

6 questions · scenario driven · every answer is recorded for your teacher

Question 1 of 6Trace
Predict first: which branch runs when the value sits exactly on the boundary?
What does this segment display when temp is 32?
IF (temp > 32) { DISPLAY "above" } ELSE { DISPLAY "at or below" }
Incorrect. IF and ELSE are mutually exclusive. Exactly one runs.
Incorrect. One of the two branches always runs when an ELSE is present.
Incorrect. Strict greater than excludes 32 itself, so the condition is false.
Correct. 32 is not greater than 32, so the condition is false and the ELSE branch runs.
Question 2 of 6Trace
What does this segment display when n is 7?
IF (n MOD 2 = 0) { DISPLAY "even" } ELSE { DISPLAY "odd" }
Incorrect. The value of n is not displayed by either branch.
Incorrect. 7 divided by 2 leaves a remainder of 1, so the condition is false.
Correct. The remainder is 1, not 0, so the ELSE branch runs and displays odd.
Incorrect. The remainder is computed but is not what gets displayed.
Question 3 of 6Debug
A grading program gives an A for 90 and above, but a student scoring exactly 90 receives a B.
Which condition most likely appears in the code?
Incorrect. This is the correct condition and would award the A.
Correct. Strictly greater than excludes the boundary, which is exactly the reported symptom: 90 falls through to the next branch.
Incorrect. This would award an A only for exactly 90, which is the opposite failure.
Incorrect. This reverses the comparison and would give an A to every failing score.
Question 4 of 6Apply
A program charges 0 dollars under 5 years old, 8 dollars from 5 to 64, and 5 dollars at 65 and above. Which set of conditions is correct and non overlapping?
Correct. Each test runs only when the previous ones failed, so the second covers 5 through 64 and the final ELSE covers 65 and up exactly.
Incorrect. This sends a 65 year old to the final branch by accident and mislabels the boundary.
Incorrect. The first test captures 5 year olds, who should pay 8, and the second captures 65 year olds, who should pay 5.
Incorrect. The second condition is always true once the first fails, so the third branch can never run.
Question 5 of 6Trace
What does this segment display when x is 4?
IF (x > 10) { DISPLAY "big" } IF (x > 2) { DISPLAY "medium" }
Incorrect. Both would display only if both conditions were true.
Incorrect. The second condition holds for 4, so something is displayed.
Incorrect. 4 is not greater than 10, so the first condition is false.
Correct. These are two independent IF statements. The first is false and the second is true, so only medium is displayed.
Question 6 of 6Analyze
A program has an IF with no ELSE, and testing shows nothing happens for certain inputs.
Which statement is accurate?
Incorrect. A false condition means the block does not run. There is no fallback.
Incorrect. An ELSE is optional in every language the course covers.
Correct. Skipping the block is exactly what a false condition means. Whether that is a bug depends on the requirement, not on the language.
Incorrect. Nothing halts. The program continues past the IF.

Where to go next

Rework the Topic 3.6 lesson and quiz Sit the Big Idea 3 unit test part A Sit the Big Idea 3 unit test part B

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