AP CSP Midterm Exam – Questions/Answers 1. A video-streaming Web site uses 32-bit integers to count the number of times each video has been played. In anticipation of some videos being played more times than can be represented with 32 bits, the Web site is planning to change to 64-bit integers for the counter. Which of the following best describes the result of using 64-bit integers instead of 32-bit integers? ✔ Ans - (C) 232 times as many values can be represented.
2. A programmer completes the user manual for a video game she has developed and realizes she has reversed the roles of goats and sheep throughout the text. Consider the programmer's goal
of changing all occurrences of "goats" to "sheep" and all occurrences of "sheep" to "goats." e programmer will use the fact that the word "foxes" does not appear anywhere in the original text.
Which of the following algorithms can be used to accomplish the programmer's goal? ✔ Ans - (C) First, change all occurrences of "goats" to "foxes." en, change all occurrences of "sheep" to "goats." Last, change all occurrences of "foxes" to "sheep."
ASCII is a character-encoding scheme that uses a numeric value to represent each character. For example, the uppercase letter "G" is represented by the decimal (base 10) value 71. A partial list of characters and their corresponding ASCII values are shown in the table below.
ASCII characters can also be represented by hexadecimal numbers. According to ASCII character encoding, which of the following letters is represented by the hexadecimal (base 16) number 56? ✔ Ans - (C) V
4. e gure below shows a circuit composed of two logic gates. e output of the circuit is true.
Which of the following is a true statement about input A? ✔ Ans - (A) Input
A must be true.
5. e following question uses a robot in a grid of squares. e robot is represented
as a triangle, which is initially in the bottom le square of the grid and facing right.
Consider the following code segment, which moves the robot in the grid. Which of the following shows the location of the robot a er running the code segment? ✔ Ans - A (triangle in middle)
6. Which of the following statements describes a limitation of using a computer simulation to model a real-world object or system? ✔ Ans - (C) Computer simulations usually make some simplifying assumptions about the real-world object or system being modeled.
7. A certain social media Web site allows users to post messages and to comment on other messages that have been posted. When a user posts a message, the message itself is considered data. In addition to the data, the site stores the following metadata.
§ e time the message was posted
§ e name of the user who posted the message
§ e names of any users who comment on the message and the times the comments were made For which of the following goals would it be more useful to analyze the data instead of the metadata? ✔ Ans - (C) To determine the topics that many users are posting about
8. e code segment below is intended to move a robot in a grid to a gray square.
e program segment uses the procedure GoalReached, which evaluates to true if the robot is in the gray square and evaluates to false otherwise. e robot in each grid is represented as a triangle and is initially facing le . e robot can move into a white or gray square but cannot move into a black region.
REPEAT UNTIL (GoalReached ())
{
IF (CAN_MOVE (forward))
{ MOVE_FORWARD ()
}IF (CAN_MOVE (right)) { ROTATE_RIGHT ()
}IF (CAN_MOVE (left))
{
ROTATE_LEFT ()
} } For which of the following grids does the code segment NOT correctly move the robot to the gray square? ✔ Ans - D (Z shape with shaded on top left corner)
9. e table below shows the time a computer system takes to complete a speci ed task on the customer data of di erent-sized companies. Based on the information in the table, which of the following tasks is likely to take the
2. A programmer completes the user manual for a video game she has developed and realizes she has reversed the roles of goats and sheep throughout the text. Consider the programmer's goal
of changing all occurrences of "goats" to "sheep" and all occurrences of "sheep" to "goats." e programmer will use the fact that the word "foxes" does not appear anywhere in the original text.
Which of the following algorithms can be used to accomplish the programmer's goal? ✔ Ans - (C) First, change all occurrences of "goats" to "foxes." en, change all occurrences of "sheep" to "goats." Last, change all occurrences of "foxes" to "sheep."
ASCII is a character-encoding scheme that uses a numeric value to represent each character. For example, the uppercase letter "G" is represented by the decimal (base 10) value 71. A partial list of characters and their corresponding ASCII values are shown in the table below.
ASCII characters can also be represented by hexadecimal numbers. According to ASCII character encoding, which of the following letters is represented by the hexadecimal (base 16) number 56? ✔ Ans - (C) V
4. e gure below shows a circuit composed of two logic gates. e output of the circuit is true.
Which of the following is a true statement about input A? ✔ Ans - (A) Input
A must be true.
5. e following question uses a robot in a grid of squares. e robot is represented
as a triangle, which is initially in the bottom le square of the grid and facing right.
Consider the following code segment, which moves the robot in the grid. Which of the following shows the location of the robot a er running the code segment? ✔ Ans - A (triangle in middle)
6. Which of the following statements describes a limitation of using a computer simulation to model a real-world object or system? ✔ Ans - (C) Computer simulations usually make some simplifying assumptions about the real-world object or system being modeled.
7. A certain social media Web site allows users to post messages and to comment on other messages that have been posted. When a user posts a message, the message itself is considered data. In addition to the data, the site stores the following metadata.
§ e time the message was posted
§ e name of the user who posted the message
§ e names of any users who comment on the message and the times the comments were made For which of the following goals would it be more useful to analyze the data instead of the metadata? ✔ Ans - (C) To determine the topics that many users are posting about
8. e code segment below is intended to move a robot in a grid to a gray square.
e program segment uses the procedure GoalReached, which evaluates to true if the robot is in the gray square and evaluates to false otherwise. e robot in each grid is represented as a triangle and is initially facing le . e robot can move into a white or gray square but cannot move into a black region.
REPEAT UNTIL (GoalReached ())
{
IF (CAN_MOVE (forward))
{ MOVE_FORWARD ()
}IF (CAN_MOVE (right)) { ROTATE_RIGHT ()
}IF (CAN_MOVE (left))
{
ROTATE_LEFT ()
} } For which of the following grids does the code segment NOT correctly move the robot to the gray square? ✔ Ans - D (Z shape with shaded on top left corner)
9. e table below shows the time a computer system takes to complete a speci ed task on the customer data of di erent-sized companies. Based on the information in the table, which of the following tasks is likely to take the
