AP CSP Practice Test 1 (10 Questions)

Bytes, which are represented by 8 bits, are the units used by computers to represent a character such as a letter or number.  The following characters are shown with their decimal representations.
C      67
K      75
.        96
p       112
Which of the above, represented in binary as a byte, contains the most zeros?

• C
• K
• .
• p

We can convert a number from decimal to octal (base 8) by repeatedly subtracting the largest possible powers of what number?

• 2
• 7
• 8
• 9

 The question below uses a simple programming language, with the following instructions.
product ← 100
REPEAT 1000 TIMES
{
     product ←product * product + 1
}
In some coding languages, the above code will result in an error.  Why?

• The fixed number of bits used to represent real numbers (as floating-point numbers) limits the range of floating-point values and mathematical operations.
• The multiple levels of abstraction used oversimplified the code.
• The value of product will always be 0.
• The fixed number of bits used to represent characters or integers limits the range of integer values and mathematical operations.

A customer is shopping online, and purchases a product advertised at $10.99.  She has a 40% discount, bringing the price to $6.594 each.  She decided to purchase 3.  Her final total should be $19.78, but the total instead is $19.77.  Choose the MOST LIKELY possible explanation for the discrepancy:

• The program calculating the total rounded the price for one of the products, then multiplied by 3.
• While multiplying the floating numbers, there was a round-off error.
• The fixed number of bits used to store the values resulted in an overflow error.
• The program does not handle signed integers.

Sort the following by levels of abstraction, from lowest to highest:
I.    logic gates
II.   operating systems
III.  programming language
IV.  machine language

• I, II, III, IV
• I, III, IV, II
• I, IV, II, III
• I, IV, III, II

Which of the following statements are true about high-level programming languages? Select TWO answers.
(I can't choose two answers on this application, so I will choose one correct answer for you and you decide the 2nd answer.)

• A high-level programming language often uses natural language elements.
• A high-level programming language does not ensure program reliability.
• A high-level programming language must be used to execute commands such as adding and multiplying
• A high-level program language allows for code re-use.

Which of the following statements is NOT correct:

• Logic gates are used to perform operations such as addition and subtraction.
• Logic gates are modeled by Boolean functions.
• Hardware is the lowest level of abstraction.
• Binary data is processed by physical layers of computing hardware.

Consider the goal of flipping two fair coins simultaneously three times and displaying the number of times both coins land on the same values (heads or tails).  Which of the following code segments can be used to accomplish that goal? Select TWO answers. (I can't choose two answers on this application, so I will choose one correct answer for you and you decide the 2nd answer.)

• a
  REPEAT 3 TIMES
  {
       IF (RANDOM(0,1) = RANDOM(0,1))
  {
            count ←count + 1
       }
  }
• b
• c
• d

Consider the procedure mystery (num, list):
PROCEDURE mystery (num, list)
{
     FOR EACH item IN list
     {
          if (list[item] MOD num == 0)
     }
          DISPLAY list[item] + " "
     REMOVE list[item]
          }
     }
}
If list myList contains the following data: [10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0], what will be displayed by mystery (3, myList)?

• 10 8 7 5 4 2 1
• 10 8 7 5 4 2 1 0
• 9 6 3
• 9 6 3 0

Consider the following procedure, cube (n), which is meant to multiply a number by itself three times.
PROCEDURE cube (n)
{
     cubeValue ← n * n * n
     RETURN (cubeValue)
}
What is returned by cube (cube(2))?

• 8
• 64
• 128
• 512