AP Computer Science Principles Practice Exam

Consider the following program. [Diagram: x ← 2; REPEAT 4 TIMES { x ← x * 3 }] Which of the following expressions represents the value stored in the variable x as a result of executing the program?

• 2 * 3 * 3 * 3

• 2 * 4 * 4 * 4

• 2 * 3 * 3 * 3 * 3

• 2 * 4 * 4 * 4 * 4

A small team of wildlife researchers is working on a project that uses motion-activated field cameras to capture images of animals at study sites. The team is considering using a “citizen science” approach to analyze the images. Which of the following best explains why such an approach is considered useful for this project?

• Distributed individuals are likely to be more accurate in wildlife identification than the research team.

• The image analysis is likely to be more consistent if completed by an individual citizen.

• The image analysis is likely to require complex research methods.

• The image analysis is likely to take a longer time for the research team than for a distributed group of individuals.

An algorithm is intended to display the following output. red red blue red red blue red red blue Which of the following code segments can be used to display the intended output?

• REPEAT 2 TIMES [ REPEAT 3 TIMES [ DISPLAY "red" ] DISPLAY "blue" ]

• REPEAT 2 TIMES [ REPEAT 3 TIMES [ DISPLAY "blue" ] DISPLAY "red" ]

• REPEAT 3 TIMES [ REPEAT 2 TIMES [ DISPLAY "red" ] DISPLAY "blue" ]

• REPEAT 3 TIMES [ REPEAT 2 TIMES [ DISPLAY "blue" ] DISPLAY "red" ]

In a certain computer program, two positive integers are added together, resulting in an overflow error. Which of the following best explains why the error occurs?

• The program attempted to perform an operation that is considered an undecidable problem.

• The precision of the result is limited due to the constraints of using a floating-point representation.

• The program can only use a fixed number of bits to represent integers; the computed sum is greater than the maximum representable value.

• The program cannot represent integers; the integers are converted into decimal approximations, leading to rounding errors.

The diagram below shows a circuit composed of three logic gates. Each gate takes two inputs and produces a single output. For which of the following input values will the circuit have an output of true?

• A = true, B = true, C = true, D = false

• A = true, B = false, C = false, D = true

• A = false, B = true, C = true, D = true

• A = false, B = false, C = true, D = true

The question below uses a robot in a grid of squares. The robot is represented as a triangle, which is initially in the bottom left square of the grid and facing right. The following programs are each intended to move the robot to the gray square. Program II uses the procedure GoalReached, which returns true if the robot is in the gray square and returns false otherwise. Program I: REPEAT 2 TIMES MOVE_FORWARD ROTATE_LEFT MOVE_FORWARD MOVE_FORWARD ROTATE_RIGHT Program II: REPEAT UNTIL GoalReached IF CAN_MOVE forward MOVE_FORWARD ELSE ROTATE_LEFT Which of the following statements best describes the correctness of the programs?

• Program I correctly moves the robot to the gray square, but program II does not.

• Program II correctly moves the robot to the gray square, but program I does not.

• Both program I and program II correctly move the robot to the gray square.

• Neither program I nor program II correctly moves the robot to the gray square.

Flight simulation software, which imitates the experience of flying, is often used to train airline pilots. Which of the following is LEAST likely to be an advantage of using flight simulation software for this purpose?

• Flight simulation software allows pilots to practice landing in a variety of different terrains and weather conditions without having to physically travel.

• Flight simulation software could save money due to the cost of maintenance and fuel for actual training flights.

• Flight simulation software provides a more realistic experience for pilots than actual training flights.

• Flight simulation software allows for the testing of emergency air situations without serious consequences.

Which of the following actions are generally helpful in program development?

I. Consulting potential users of the program to identify their concerns

II. Writing and testing small code segments before adding them to the program

III. Collaborating with other individuals when developing a large program

• I and II only

• I and III only

• II and III only

• I, II, and III

An Internet user has a need to send private data to another user. Which of the following provides the most security when transmitting private data?

• Certifying the data with a Creative Commons license before sending it

• Sending the data using a high-bandwidth connection

• Sending the data using public-key encryption

• Sending the data using redundant routing

Ticket prices for a science museum are shown in the following table. | Type of Ticket | General Admission Cost (in dollars) | Guided Tour Cost (in dollars) | |-------------------------|-------------------------------------|-------------------------------| | Regular (ages 13 and up)| 8 | 10 | | Child (ages 12 and below)| 6 | 8 | A programmer is creating an algorithm to display the cost of a ticket based on the information in the table. The programmer uses the integer variable age for the age of the ticket recipient. The Boolean variable includesTour is true when the ticket is for a guided tour and is false when the ticket is for general admission. Which of the following code segments correctly displays the cost of a ticket?

• (A) cost ← 6 IF ((age > 12) OR includesTour) { cost ← cost + 2 } DISPLAY (cost)

• (B) cost ← 6 IF (age > 12) { cost ← cost + 2 } IF (includesTour) { cost ← cost + 2 } DISPLAY (cost)

• (C) cost ← 6 IF (age > 12) { IF (includesTour) { cost ← cost + 2 } } DISPLAY (cost)

• (D) cost ← 6 IF (age > 12) { cost ← cost + 2 } ELSE { IF (includesTour) { cost ← cost + 2 } } DISPLAY (cost)