Computational Thinking Unit 1

Which of the following is an important step to take before beginning to write the code for a program?

• Randomly generate the variable names to be used in the program

• Write on paper or a whiteboard all the code you intend to type

• Plan the logic and anticipated input/output of the code

• Plan an update and maintenance schedule for the program

Which of the following could be considered part of the beginning “state” of a Scratch program?

• Visibility of sprites

• The background image

• The value of a variable

• All of the above

As part of the lifecycle of a program, after a computer programmer writes the code, it is then compiled and usually used to create an executable file to be run on the CPU. The code that is run through the compiler is known as what?

• Machine Code

• Source Code

• Source Code (C) Binary Code

• RAM

The following two algorithms are designed to find the minimum value in a list of integers.

Algorithm I: Create a variable min, and set this to the first value in the list. Compare each subsequent value in the list against the value of min, and if it is smaller than or equal to the current value, set min to this value. When the end of the list is reached, display the value of min.

Algorithm II: Create a variable min, and set this to 0. Compare each value in the list against the value of min, and if it is smaller than the current value, set min to this value. When the end of the list is reached, display the value of min.

Which of the following statements correctly demonstrates that the two algorithms are NOT equivalent?

• Both algorithms will correctly display the minimum value of the list [-1, 3, -4, 8]

• Neither algorithm will correctly display the minimum value of the list [0, 5, 6, 2]

• Algorithm I will correctly display the minimum value of the list [4, 10, 6, 1], but Algorithm II will not

• Algorithm II will correctly display the minimum value of the list [-4, 2, 3, 2], but Algorithm I will not

Many tasks, large and small, can be solved by performing a specific set of actions and making a particular set of decisions in very precise ways. These sets of actions and decisions are known as what?

• Abstraction

• Algorithms

• Building Blocks

• Processes

An office building has two floors. A computer program is used to control an elevator that travels between the two floors. Physical sensors are used to set the following Boolean variables.

Variable 1: onFloor1 Description: Set to true if the elevator is stopped on floor 1; otherwise set to false

Variable 2: onFloor2 Description: Set to true if the elevator is stopped on floor 2; otherwise set to false

Variable 3: callTo1 Description: Set to true if the elevator is called to floor 1; otherwise set to false

Variable 4: callTo2 Description: Set to true if the elevator is called to floor 2; otherwise set to false

The elevator moves when the door is closed and the elevator is called to the floor that it is not currently on. Which of the following Boolean expressions can be used in a selection statement to cause the elevator to move?

• (onFloor1 AND callTo2) AND (onFloor2 AND callTo1)

• (onFloor1 AND callTo2) OR (onFloor2 AND callTo1)

• (onFloor1 OR callTo2) AND (onFloor2 OR callTo1)

• (onFloor1 OR callTo2) OR (onFloor2 OR callTo1)

Which of the following types of languages is optimized for machine processing and may be written and expressed as a series of binary digits (e.g., ones and zeros), making it difficult for humans to read and write?

• Natural language

• Pseudocode

• High-level programming language

• Low-level programming language

Consider constructing an algorithm for a robot that can only perform the following three predefined operations.

MOVE_FORWARD ( ): The robot moves one square forward in the direction it is facing.

ROTATE_LEFT ( ): The robot rotates in place 90 degrees counterclockwise (i.e., makes an in-place left turn).

ROTATE_RIGHT ( ): The robot rotates in place 90 degrees clockwise (i.e., makes an in-place right turn).

Which of the following algorithms will successfully cause the robot to trace out a squareshaped path, with the robot ending up in its original position and facing in its original direction?

• Step 1: MOVE_FORWARD ( )

  Step 2: ROTATE_RIGHT ( )

  Step 3: MOVE_FORWARD ( )

  Step 4: ROTATE_RIGHT ( )

  Step 5: MOVE_FORWARD ( )

  Step 6: ROTATE_RIGHT ( )

  Step 7: MOVE_FORWARD ( )

• Step 1: MOVE_FORWARD ( )

  Step 2: MOVE_LEFT ( )

  Step 3: MOVE_BACKWARD ( )

  Step 4: MOVE_RIGHT ( )

• Step 1: MOVE_FORWARD ( )

  Step 2: ROTATE_LEFT ( )

  Step 3: MOVE_FORWARD ( )

  Step 4: ROTATE_LEFT ( )

  Step 5: MOVE_FORWARD ( )

  Step 6: ROTATE_LEFT ( )

  Step 7: MOVE_FORWARD ( )

  Step 8: ROTATE_LEFT ( )

• Step 1: MOVE_FORWARD ( )

  Step 2: TURN_LEFT ( )

  Step 3: Repeat steps 1 and 2 four more times.

Which of the following statements about high-level programming languages when compared to low-level programming languages is true?

• High-level programming languages provide programmers with more abstractions and are easier for people to read

• High-level programming languages provide programmers with more abstractions but are more difficult for people to read

• High-level programming languages provide programmers with less abstractions but are easier for people to read

• High-level programming languages provide programmers with less abstractions and are more difficult for people to read

Joanna wishes to create a variable in her scratch game which records the number of seconds until the game ends. Which of the following would be the most appropriate name for this variable?

• Variable1

• t

• amountOfTimeRemainingInTheGame

• time_left