Data Types

Question 1

What is an Integer

Answer 1

• A whole number
• Zero is an integer
• Negative numbers are integers
• Can’t have a fractional part

Question 2

What is a Real Number

Answer 2

• Positive or negative numbers
• Can have a fractional part

Question 3

What is a Character

Answer 3

• A single symbol used by a computer
• The letters A to Z
• The numbers 0​ to 9
• Symbols like %, £, and,

Question 4

What is a String

Answer 4

• A collection of characters
• Can be used to store a single character or many characters in succession
• Don’t cut off leading 0​s like numeric types

Question 5

What is a Boolean

Answer 5

Value restricted to True​ and False

Question 6

What are the names for how binary is stored

Answer 6

• Bit - single binary digit
• Nibble - 4-bits grouped together
• Byte - 8-bits or 2-nibbles grouped together

Question 7

What are the Binary Addition Rules

Answer 7

• 0 + 0 = 0
• 0 + 1 = 1
• 1 + 0 = 1
• 1 + 1 = 0 carry 1

Question 8

Convert the following Binary to Decimal

• 0110 1010
• 0000 1000
• 0001 1001
• 1100 0010
• 0101 0100

Answer 8

0110 1010 - 106

0000 1000 - 8

0001 1001 - 25

1100 0010 - 194

0101 0100 - 84

Question 9

Convert the following Decimal to Binary

• 10
• 84
• 160
• 53
• 137

Answer 9

10 - 0000 1010

84 - 0101 0100

160 - 1010 0000

53 - 0011 0101

137 - 1000 1001

Question 10

What are the two ways negative numbers are represented in binary

Answer 10

• Sign magnitude
• Two’s complement

Question 11

How do you convert a Binary Number into a negative number using Sign Magnitude

Answer 11

• A leading 1​ is added for a negative number
• A leading 0​ is added for a positive number

Question 12

Convert the decimal number -21 into a two’s complement binary number (Method)

Answer 12

128 64 32 16 8 4 2 1

0 0 0 1 0 1 0 1

One’s Complement (Flip) - 1 1 1 0 1 0 1 0

Two’s Complement (+1) - 1 1 1 0 1 0 1 1

Answer = 1110 1011

Question 13

Subtract the binary number

0000 1111 from 1001 0100

Answer 13

Two’s Complement 0000 1111 = 1111 0001

Add the two numbers - 1001 0100

+ 1111 0001

=[1] 1000 0101

Answer = 1000 0101

Question 14

Compare Decimal and Hexadecimal Numbers

Answer 14

Question 15

Convert the binary 1111 0101 into hexadecimal

Answer 15

Split into 4 - 1111 0101

Work out the value of both parts - 1111 = 15 0101 = 5

Convert into Hexadecimal - 15 = F 5 = 5

Answer = F5

Question 16

What is the Mantissa and Exponent of 123

Answer 16

Mantissa - 1.23

Exponent - x 10^2

Question 17

Convert the decimal number 50 into a two complement floating point binary number using a 8-bit Mantissa and a 4-bit Exponent

Answer 17

Write in Binary - 1 1 0 0 1 0

Normalise the number (reposition decimal point in front of first 1) - 0.110010 x 2^6

Answer =

Mantissa = 01100100 Exponent = 0110

Question 18

Convert the decimal number 0.375 into a two’s complement floating point binary number using a 4-bit Mantissa and 4-bit Exponent

Answer 18

Write in Binary - 0 . 0 1 1

Normalise the number - 0. 1 1 x 2^-1

Answer =

Mantisaa = 0110 Exponent = 1111

Question 19

Convert the decimal number -21 into a two’s complement floating point number using a 8-bit Mantissa and 4-bit Exponent

Answer 19

Write in Binary - 1 0 1 0 1

Normalise the number - 0. 1 0 1 0 1 0 0 x 2^5

Two’s Complement - 1. 0 1 0 1 1 0 0

Answer =

Mantissa = 1010 1100 Exponent = 0101

Question 20

Convert the floating point number 011100 001 into decimal

Answer 20

Convert Exponent into Decimal = 1

Truncate (opposite of Normalise) the Mantissa = 0. 1 1 1

Move point back 1 space = 1. 1 1

Convert into Decimal - 1.75

Answer = 1.75

Question 21

How do you add floating point numbers

Answer 21

• To add floating point binary numbers, their exponents need to be the same
• Then add the mantissas
• Finally, normalise the result if required

Question 22

How do you subtract floating point numbers

Answer 22

• Involves converting to two’s complement and adding
• The exponents must be the same
• Use binary addition on the mantissas
• Normalise the result if required

Question 23

What is a Logical Shift

Answer 23

• A logical shift involves moving all of the bits in a binary number a specified number of places to the right or to the left
• Can be thought of as adding a number of leading or trailing zeros
• The result is a multiplication (or division if shifting right) by two to the power of the number of places shifted
• A logical shift left by one place has the effect of doubling the initial number

Question 24

What happens when you mask a binary number

Answer 24

When you use binary numbers by combining them with a logic gate

Question 25

What is a Character Set

Answer 25

• A published collection of codes and corresponding characters
• Can be used by computers for representing text
• Two widely used character sets are ASCII and Unicode

Question 26

What is ASCII Code

Answer 26

• American Standard Code for Information Interchange
• The leading character set before Unicode
• Uses 7 bits to represent 128 different characters
• ASCII soon came into trouble when computers needed to represent other languages with different characters

Question 27

What is Unicode

Answer 27

• Solves the problem of ASCII’s limited character set
• Uses a varying number of bits allowing for over 1 million different characters
• Many characters have yet to be allocated
• Enough capacity to represent a wealth of different languages, symbols, and emoji