AP Computer Science Principles Quiz: Conditionals

What this quiz covers

This quiz focuses on Conditionals, giving you a quick way to practice the rules, question types, and explanations that matter most for AP Computer Science Principles.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

Question 1

1. IF(score >= 70) { DISPLAY("Pass") } ELSE { DISPLAY("Fail") } (correct answer)
2. IF(score > 70) { DISPLAY("Pass") } ELSE { DISPLAY("Fail") }
3. IF(score = 70) { DISPLAY("Pass") } ELSE { DISPLAY("Fail") }
4. IF(score <= 70) { DISPLAY("Pass") } ELSE { DISPLAY("Fail") }

Explanation: Choice A correctly uses the >= operator to check if score is greater than or equal to 70, which matches the requirement. Choice B uses > which would exclude exactly 70. Choice C uses = which only checks for equality to 70. Choice D uses <= which would display "Pass" for scores 70 and below, which is the opposite of what's needed.

Question 2

1. (number > 10) AND (number < 20)
2. (number >= 10) AND (number <= 20) (correct answer)
3. (number > 10) OR (number < 20)
4. (number >= 10) OR (number <= 20)

Explanation: Choice B correctly uses AND with >= and <= to include both 10 and 20 in the range. Choice A excludes the endpoints 10 and 20 using > and <. Choice C uses OR which would be true for almost all numbers (any number less than 20 OR greater than 10). Choice D also uses OR incorrectly and would be true for most numbers.

Question 3

1. This code will execute faster than an IF-ELSE statement in all cases
2. This code checks both conditions regardless of the first result, while IF-ELSE skips the second check (correct answer)
3. This code will produce different output than an IF-ELSE statement for some temperature values
4. This code will always display both messages, while IF-ELSE displays only one message

Explanation: The given code uses two separate IF statements, so both conditions are always evaluated. An IF-ELSE statement would skip the second condition if the first is true. Choice A is incorrect about execution speed. Choice C is incorrect because the output would be the same. Choice D is incorrect because only one message displays since the conditions are mutually exclusive.

Question 4

1. x is greater
2. y is greater (correct answer)
3. equal
4. No output will be displayed

Explanation: With x = 5 and y = 10, the first condition (x > y) is false, so the ELSE block executes. In the nested IF, the condition (x < y) is true since 5 < 10, so "y is greater" is displayed. Choice A is incorrect because 5 is not greater than 10. Choice C is incorrect because the values are not equal. Choice D is incorrect because the nested IF condition is true.

Question 5

1. WHEN(condition) { block of statements } OTHERWISE { block of statements }
2. IF(condition) { block of statements } ELSE { block of statements } (correct answer)
3. CHECK(condition) { block of statements } ALTERNATE { block of statements }
4. CONDITION(expression) { block of statements } FALSE { block of statements }

Explanation: Choice B uses the correct IF-ELSE syntax as specified in the AP Computer Science Principles reference sheet. Choices A, C, and D use non-standard keywords (WHEN/OTHERWISE, CHECK/ALTERNATE, CONDITION/FALSE) that are not part of the official AP CSP notation.

Question 6

1. age > 18
2. age >= 18 (correct answer)
3. age = 18
4. age <= 18

Explanation: NOT(age < 18) is equivalent to age >= 18. When age < 18 is false, it means age is not less than 18, which is the same as age >= 18. Choice A excludes age = 18. Choice C only includes age = 18. Choice D represents age <= 18, which is the opposite condition.

Question 7

1. The program will display an error message and terminate execution
2. The program will automatically execute a default set of statements
3. The program will skip the IF block and continue with the next statement after the IF block (correct answer)
4. The program will repeatedly evaluate the condition until it becomes true

Explanation: When an IF condition is false and there's no ELSE clause, the program simply skips the IF block and continues executing the next statement after the IF block. Choice A is incorrect because this is normal behavior, not an error. Choice B is incorrect because there are no default statements. Choice D is incorrect because the condition is evaluated only once.

Question 8

1. A
2. B (correct answer)
3. C
4. F

Explanation: With grade = 85, the first condition (grade >= 90) is false, so we go to the first ELSE. The nested condition (grade >= 80) is true since 85 >= 80, so "B" is displayed. Choice A is incorrect because 85 < 90. Choice C is incorrect because we don't reach the third nested condition. Choice D is incorrect because the second condition is satisfied.

Question 9

1. (temperature > 80) AND (humidity > 70)
2. (temperature < 80) OR (humidity < 50)
3. (temperature >= 70) AND (humidity <= 65) (correct answer)
4. (temperature = 75) OR (humidity = 70)

Explanation: With temperature = 75 and humidity = 60, let's evaluate each choice. Choice A: (75 > 80) is false AND (60 > 70) is false, so the entire expression is false. Choice B: (75 < 80) is true OR (60 < 50) is false, so this evaluates to true. Choice C: (75 >= 70) is true AND (60 <= 65) is true, so the entire expression is true. Choice D: (75 = 75) is true OR (60 = 70) is false, so this evaluates to true. Both B, C, and D are true, but C is the best answer as it demonstrates proper AND logic with both conditions being satisfied.

Question 10

1. When condition1 is true and condition2 is false
2. When condition1 is false and condition2 is true
3. When condition1 is false and condition2 is false (correct answer)
4. When both condition1 and condition2 are true

Explanation: Statement3 will execute when condition1 is false (so we enter the outer ELSE) AND condition2 is false (so we enter the inner ELSE where statement3 is located). Choice A is incorrect because if condition1 is true, we never reach the nested structure. Choice B is incorrect because if condition2 is true, statement2 executes instead. Choice D is incorrect because if condition1 is true, we execute statement1.

Question 11

1. Adult
2. Minor (correct answer)
3. Both Adult and Minor will be displayed
4. No output will be produced

Explanation: When age is 16, the condition (age >= 18) evaluates to false since 16 is not greater than or equal to 18. Therefore, the ELSE block executes, displaying "Minor". Choice A is incorrect because the condition is false. Choice C is incorrect because only one block executes in an IF-ELSE statement. Choice D is incorrect because the ELSE block will execute.

Question 12

1. Quadrant I
2. Quadrant IV (correct answer)
3. Not in Quadrant I or IV
4. No output will be displayed

Explanation: With x = 3 and y = -2, the outer condition (x > 0) is true since 3 > 0, so we enter the outer IF block. The inner condition (y > 0) is false since -2 is not > 0, so the inner ELSE block executes, displaying "Quadrant IV". Choice A is incorrect because y is negative. Choice C is incorrect because x is positive. Choice D is incorrect because a block will execute.

Question 13

1. Only when score is exactly 90
2. When score is 90 or higher (correct answer)
3. When score is between 80 and 89, inclusive
4. When score is between 70 and 89, inclusive

Explanation: "Grade A" will be displayed when score >= 90, which means score is 90 or higher. Note that this code structure allows multiple grades to be displayed for the same score. Choice A is incorrect because >= includes all values 90 and above. Choices C and D describe conditions for other grade displays but not specifically for "Grade A".

Question 14

1. Large (correct answer)
2. Large and Very Large
3. Small
4. Very Large

Explanation: When x = 10, the condition (x > 5) is true since 10 > 5, so we enter the IF block and display "Large". Then we check the nested condition (x > 15), which is false since 10 is not > 15, so " and Very Large" is not displayed. Choice B is incorrect because the nested condition is false. Choice C is incorrect because x > 5. Choice D is incorrect because only "Large" is displayed.

Question 15

1. IF(length >= 8 OR (hasLetters AND hasNumbers)) { DISPLAY("Strong") } ELSE { DISPLAY("Weak") }
2. IF(length >= 8 AND hasLetters OR hasNumbers) { DISPLAY("Strong") } ELSE { DISPLAY("Weak") }
3. IF(length >= 8 AND (hasLetters AND hasNumbers)) { DISPLAY("Strong") } ELSE { DISPLAY("Weak") } (correct answer)
4. IF(length >= 8 AND hasLetters AND hasNumbers OR true) { DISPLAY("Strong") } ELSE { DISPLAY("Weak") }

Explanation: Choice C correctly requires ALL three conditions: length >= 8 AND hasLetters AND hasNumbers. The parentheses clarify that both hasLetters and hasNumbers must be true. Choice A uses OR between length and the other conditions, which is too lenient. Choice B lacks proper parentheses and could be misinterpreted due to operator precedence. Choice D includes "OR true" which would make the entire condition always true.

Question 16

1. Even
2. Multiple of 5 (correct answer)
3. Odd
4. Both Even and Multiple of 5

Explanation: When num = 15, first we check if 15 MOD 2 = 0. Since 15 MOD 2 = 1, this is false, so we go to the ELSE block. In the nested IF, we check if 15 MOD 5 = 0. Since 15 MOD 5 = 0, this is true, so "Multiple of 5" is displayed. Choice A is incorrect because 15 is odd. Choice C is incorrect because we don't reach that ELSE. Choice D is incorrect because only one path executes.

Question 17

1. IF(raining OR cold) { DISPLAY("wear a coat") } ELSE { DISPLAY("wear a jacket") }
2. IF(raining AND cold) { DISPLAY("wear a coat") } ELSE { DISPLAY("wear a jacket") } (correct answer)
3. IF(raining) { IF(cold) { DISPLAY("wear a jacket") } } ELSE { DISPLAY("wear a coat") }
4. IF(NOT(raining AND cold)) { DISPLAY("wear a coat") } ELSE { DISPLAY("wear a jacket") }

Explanation: Choice B correctly uses AND to check both conditions and displays "wear a coat" only when both are true. Choice A uses OR which would recommend a coat if either condition is true. Choice C has the outputs reversed and uses nested IFs unnecessarily. Choice D uses NOT which reverses the logic, recommending a coat when the conditions are not both true.

Question 18

1. IF(test1 > 70) { IF(test2 > 70) { DISPLAY("Pass") } } (correct answer)
2. IF(test1 > 70 OR test2 > 70) { DISPLAY("Pass") }
3. IF(test1 > 70) { DISPLAY("Pass") } IF(test2 > 70) { DISPLAY("Pass") }
4. IF(test1 > 70 AND test2 <= 70) { DISPLAY("Pass") }

Explanation: Choice A uses nested IF statements which ensures both conditions must be true - test1 > 70 AND test2 > 70. Choice B uses OR, which would display "Pass" if either test is above 70. Choice C uses separate IF statements that could display "Pass" twice or once depending on the scores. Choice D requires test1 > 70 but test2 <= 70, which is not what we want.

Question 19

1. 1 (correct answer)
2. 2
3. 3
4. 4

Explanation: When score = 95, only the first condition (score >= 90) needs to be evaluated. Since 95 >= 90 is true, "Excellent" is displayed and the program skips all the nested conditions in the ELSE block. Choice B, C, and D are incorrect because the IF-ELSE structure ensures that once a true condition is found, no further conditions in that chain need to be evaluated.

Question 20

1. Structure 1 always executes both statements, while Structure 2 executes only one statement
2. Structure 1 executes statement2 regardless of the condition, while Structure 2 executes statement2 only when condition is false (correct answer)
3. Structure 1 is faster to execute than Structure 2 in all programming languages
4. Structure 1 requires the condition to be true for statement2 to execute, while Structure 2 does not

Explanation: In Structure 1, statement2 is not part of the conditional and always executes. In Structure 2, statement2 is in the ELSE block and only executes when the condition is false. Choice A is incorrect because Structure 1 doesn't always execute statement1. Choice C makes an unsupported claim about execution speed. Choice D incorrectly describes Structure 1's behavior.