--- title: "AP Computer Science A Unit 2 Practice Test" description: "A timed AP Computer Science A Unit 2 (Selection and Iteration) practice test in the AP format, drawn from 1,128 multiple-choice questions and 34 FRQs written for the unit. The standard version takes about 66 minutes." canonical: "https://fiveable.me/ap-comp-sci-a/unit-test/2" type: "unit-test" subject: "AP Computer Science A" unit: "Unit 2" --- # AP Computer Science A Unit 2 Practice Test ## Overview A timed AP Computer Science A Unit 2 (Selection and Iteration) practice test in the AP format, drawn from 1,128 multiple-choice questions and 34 FRQs written for the unit. The standard version takes about 66 minutes. ## Test Format - 20 Multiple Choice Questions (43 minutes) - 1 FRQ – FRQ 1 – Methods and Control Structures (23 minutes) ## Unit FRQs by Type - [FRQ 1 – Methods and Control Structures](/ap-comp-sci-a/frqs/methods-and-control-structures?unit=2): 34 questions ## Practice Questions ### Question 1 **Countdown Accumulator with while Loop** > Consider the following Java code. > > ```java > public class CountDown { > public static int compute(int n) { > int total = 0; > int k = n; > while (k > 0) { > total += k; > k -= 2; > } > return total; > } > > public static void main(String[] args) { > int result = compute(7); > System.out.println(result); > > int x = 0; > int limit = 4; > while (x < limit) { > System.out.print(x + " "); > x++; > } > } > } > ``` Source: Fiveable fictional Java practice code aligned to the AP Computer Science A Fall 2025 CED What is printed to the console as a result of executing the main method in the code shown? - (A) 16 0 1 2 3 - (B) 16 0 1 2 3 4 - (C) 12 0 1 2 3 - (D) 16 1 2 3 4 **Answer: (A)** Tracing compute(7): iteration 1 k=7, total=7, k becomes 5; iteration 2 k=5, total=12, k becomes 3; iteration 3 k=3, total=15, k becomes 1; iteration 4 k=1, total=16, k becomes -1; condition -1>0 is false, loop exits, returns 16. println(16) prints '16' then newline. Second loop: x starts at 0, limit=4. Prints '0 ', '1 ', '2 ', '3 ', then x=4 fails x<4, loop ends. Full output is '16' on line 1 and '0 1 2 3 ' on line 2. ### Question 2 Consider the following code segment. ```java int count = 0; for (int i = 0; i < 4; i++) { for (int j = i; j < 4; j++) { if ((i + j) % 2 == 0) { count++; } } } System.out.println(count); ``` What is printed as a result of executing this code segment? - (A) `6` - (B) `8` - (C) `10` - (D) `16` **Answer: (A)** Tracing the nested loops shows the inner loop's starting value depends on the outer loop variable `i`. The condition `(i + j) % 2 == 0` is true when `i` and `j` are both even or both odd. The matching `(i, j)` pairs are (0,0), (0,2), (1,1), (1,3), (2,2), and (3,3), which increments `count` a total of 6 times. ### Question 3 Consider the following code segment. ```java String result = ""; for (int i = 1; i <= 3; i++) { for (int j = 1; j <= i; j++) { result += (i * j) + " "; } } System.out.println(result); ``` What is printed as a result of executing this code segment? - (A) `"1 2 4 3 6 9 "` - (B) `"1 2 2 4 3 6 "` - (C) `"1 2 2 3 3 3 "` - (D) `"1 1 2 1 2 3 "` **Answer: (A)** The outer loop runs from 1 to 3, and the inner loop runs from 1 to the current value of `i`. The code concatenates the product of `i` and `j`. For `i=1`, it appends 1*1. For `i=2`, it appends 2*1 and 2*2. For `i=3`, it appends 3*1, 3*2, and 3*3. ### Question 4 Consider the following code segment. ```java int val = 20; for (int i = 1; i < 4; i++) { int j = i; while (j > 0) { val -= j; j--; } } System.out.println(val); ``` What is printed as a result of executing this code segment? - (A) `10` - (B) `14` - (C) `0` - (D) `17` **Answer: (A)** The outer `for` loop runs for `i` values 1, 2, and 3. The inner `while` loop subtracts all integers from `i` down to 1 from `val`. It subtracts 1 (when i=1), then 2+1=3 (when i=2), then 3+2+1=6 (when i=3). The total subtracted is 10, leaving `val` as 10. ### Question 5 Consider the following code segment. ```java int total = 0; for (int i = 1; i <= 4; i++) { for (int j = 1; j <= 4; j++) { if (j > i) { break; } total += j; } } System.out.println(total); ``` What is printed as a result of executing this code segment? - (A) `20` - (B) `10` - (C) `30` - (D) `40` **Answer: (A)** The `break` statement causes the inner loop to terminate early when `j > i`. This means `j` only takes on values from 1 up to `i`. The code sums these values: 1 (for i=1), 1+2 (for i=2), 1+2+3 (for i=3), and 1+2+3+4 (for i=4), resulting in 1 + 3 + 6 + 10 = 20. ### Question 6 Consider the following code segment. ```java double val = 0; int divisor = 2; for (int i = 0; i < 2; i++) { val += 11 / divisor; divisor += 3; } System.out.println(val); ``` What is printed as a result of executing this code segment? - (A) 7.0 - (B) 7.7 - (C) 8.0 - (D) 5.0 **Answer: (A)** Tracing a loop containing integer division and automatic widening. In the first iteration, `11 / 2` evaluates to `5` (integer division), which widens to `5.0`. In the second iteration, `11 / 5` evaluates to `2`, widening to `2.0`. The sum is `7.0`. ### Question 7 Consider the following code segment. ```java int total = 0; int count = 5; while (count > 2) { total += count; count--; } total *= count; System.out.println(total); ``` What is printed as a result of executing this code segment? - (A) 24 - (B) 14 - (C) 27 - (D) 60 **Answer: (A)** Analyzing loop execution with decrement operators requires tracking the loop control variable and the accumulator. The loop runs for `count` values of 5, 4, and 3, adding them to `total` to reach 12. The loop terminates when `count` becomes 2, and the final statement multiplies `total` (12) by the current `count` (2) to yield 24. ### Question 8 The following method is intended to return a new string containing the characters of `word` in reverse order. ```java public static String reverse(String word) { String result = ""; /* missing code */ return result; } ``` Which of the following can replace `/* missing code */` to correctly reverse the string? - (A) `for (int i = 0; i < word.length(); i++) { result = word.charAt(i) + result; }` - (B) `for (int i = 0; i < word.length(); i++) { result = result + word.charAt(i); }` - (C) `for (int i = 1; i < word.length(); i++) { result = word.charAt(i) + result; }` - (D) `for (int i = 1; i <= word.length(); i++) { result = result + word.charAt(i); }` **Answer: (A)** Evaluating string concatenation order within a forward-iterating loop. By iterating from the beginning of the string and prepending each character (`word.charAt(i) + result`), the characters are accumulated in reverse order. ### Question 9 The following method is intended to return a new string with all lowercase vowels (`"a"`, `"e"`, `"i"`, `"o"`, `"u"`) removed from the parameter `word`. ```java public static String removeVowels(String word) { String result = ""; for (int i = 0; i < word.length(); i++) { String letter = word.substring(i, i + 1); if (/* missing code */) { result += letter; } } return result; } ``` Which of the following can replace `/* missing code */` so the method works as intended? - (A) `"aeiou".indexOf(letter) == -1` - (B) `"aeiou".indexOf(letter) >= 0` - (C) `"aeiou".indexOf(letter) != -1` - (D) `"aeiou".indexOf(letter) == 1` **Answer: (A)** Utilizing the `indexOf` method to filter characters. The `indexOf` method returns `-1` when a substring is not found within the target string. Checking for `-1` ensures the current letter is not a vowel before appending it to the result. ### Question 10 A meteorologist has two datasets: Dataset 1 contains `cityID` and `averageTemp` (a `double`). Dataset 2 contains `cityID` and `currentTemp` (a `double`). The meteorologist evaluates the Boolean expression `currentTemp <= averageTemp - 10.0` for a specific city. What knowledge is extracted when this expression evaluates to `true`? - (A) The city's current temperature is at least ten degrees below its historical average. - (B) The city's current temperature is exactly ten degrees below its historical average. - (C) The city's current temperature is at most ten degrees above its historical average. - (D) The city's current temperature is more than ten degrees above its historical average. **Answer: (A)** Evaluating the `<=` operator requires recognizing that it checks for values less than or equal to a threshold. Since the threshold is the average temperature minus 10.0, a true result indicates the current temperature is at least ten degrees colder than the historical average. ## Review the Unit - [2.1 Algorithms with Selection and Repetition](/ap-comp-sci-a/unit-2/algorithms-with-selection-and-repetition/study-guide/42crNSZyW8IRsntk9IHe) - [2.2 Boolean Expressions](/ap-comp-sci-a/unit-2/boolean-expressions/study-guide/s6j4i9ram3AlCg3uYjwd) - [2.3 If Statements and Control Flow](/ap-comp-sci-a/unit-2/if-statements-and-control-flow/study-guide/IbxsFeJQ5T1FNNBEWErO) - [2.4 If-Else Statements](/ap-comp-sci-a/unit-2/if-else-statements/study-guide/t6FfmE9rwA4mdWqv2ogR) - [2.5 Compound Boolean Expressions](/ap-comp-sci-a/unit-2/compound-boolean-expressions/study-guide/WVkDsh43kiP30BIqg3Sh) - [2.6 Equivalent Boolean Expressions](/ap-comp-sci-a/unit-2/equivalent-boolean-expressions/study-guide/aMDnyFuOcAXnZigLW1vL) - [2.7 While Loops](/ap-comp-sci-a/unit-2/while-loops/study-guide/7qGsGOh1UKALAWpJhZOi) - [2.8 For Loops](/ap-comp-sci-a/unit-2/for-loops/study-guide/DJuLxKz6SiSAX2cEVmCt) - [2.9 Implementing Selection and Iteration Algorithms](/ap-comp-sci-a/unit-2/implementing-selection-and-iteration-algorithms/study-guide/ulqF0nPukr6rbwgDTCuU) - [2.10 Developing Algorithms Using Strings](/ap-comp-sci-a/unit-2/developing-algorithms-using-strings/study-guide/hDOL1VhnMQFPkBf6xMMW) - [2.11 Nested Iteration](/ap-comp-sci-a/unit-2/nested-iteration/study-guide/Buapg1KURHNbw6yRY8EZ) - [2.12 Informal Code Analysis](/ap-comp-sci-a/unit-2/informal-code-analysis/study-guide/CR84MbOE4FDDoSVokDVZ) ## Other Unit Tests - [Unit 1: Using Objects and Methods](/ap-comp-sci-a/unit-test/1) - [Unit 3: Class Creation](/ap-comp-sci-a/unit-test/3) - [Unit 4: Data Collections](/ap-comp-sci-a/unit-test/4) ## About This Document Canonical Fiveable pages are available as Markdown at the same path plus `.md`. - [llms.txt](https://fiveable.me/llms.txt): index of Fiveable's sections and URL patterns - [llms-full.txt](https://fiveable.me/llms-full.txt): complete subject and unit listing - [MCP server](https://fiveable.me/mcp): call Fiveable as tools instead of fetching pages (`https://fiveable.me/api/mcp`) - [MCP server for AP teachers](https://fiveable.me/mcp/teachers): a teacher's classes, assignments and AP-rubric grading (`https://fiveable.me/api/mcp/teacher`)