Data types

Question 1

What does an AND operator do? (Mask)

Answer 1

AND operator is used to clear a particular bit, leaves the other bits unchanged

Question 2

AND 1 and 0 meaning

Answer 2

Use 1 to keep the number the same
Use 0 to change the number

Question 3

What does an OR operator do? (Mask)

Answer 3

OR operator used to set a particular bit, leaves the other bits unchanged

Question 4

OR 0 and 1 meaning

Answer 4

0 the keep the number the same
1 to change/set the number

Question 5

What does a XOR operator do? (Mask)

Answer 5

XOR operator used to toggle a particular bit, leaves the other bits unchanged

Question 6

XOR 0 and 1 meaning

Answer 6

1 toggles the number
0 keeps the number the same

Question 7

And truth table

Answer 7

0+0=0
0+1=0
1+0=0
1+1=1

Question 8

OR truth table

Answer 8

0+0=0
0+1=1
1+0=1
1+1=1

Question 9

XOR truth table

Answer 9

0+0=0
0+1=1
1+0=1
1+1=0

Question 10

What mask do you use to make lowercase

Answer 10

Apply OR mask
0010 0000

Question 11

What mask do you use to make uppercase

Answer 11

AND mask
1101 1111

Question 12

Normalised floating point rules

Answer 12

Mantissa always starts with:
01 for positive numbers
or
10 for negative numbers

Question 13

Why should you use the correct data type

Answer 13

Different data types take up different amounts of memory. To optimise program performance it’s important to use the correct data type where possible

Question 14

What are the different data types

Answer 14

Integer
Real/float
Boolean
Character
String

Question 15

Define primitive data type

Answer 15

Any basic data type provided by a language as a foundational building block

Question 16

Define composite data type

Answer 16

Most languages allow more complex data types to be constructed from primitive data types

Question 17

Define integer

Answer 17

Integer data type represents any positive or negative whole nunber

Question 18

Define real

Answer 18

The real data type represents any positive or negative number including decimals or fractions

Question 19

Define character

Answer 19

The character data type represents a single character (symbol or letter)

Question 20

Define string

Answer 20

The string data type represents a collection of characters (not limited to letters)

Question 21

Define Boolean

Answer 21

The Boolean data type can be used to represent one of two truth values associated with logic

Question 22

Define casting

Answer 22

A way to convert one data type to another

Question 23

What is sign and magnitude

Answer 23

A way of representing negative numbers

Question 24

What does a positive number start with (S+M)

Answer 24

Positive numbers start with a 0

Question 25

What does a negative number start with (S+M)

Answer 25

A negative number starts with a 1

Question 26

What does the most significant bit represent (S+M)

Answer 26

It becomes a sign bit- so it no longer holds a value

Question 27

What is the largest positive and negative number: (S+M)

Answer 27

Positive: 127
0111 1111
Negative: -127
1111 1111

Question 28

Disadvantages of S+M

Answer 28

There is +0 and -0
Two different types of data that are being represented with one number
Not useful for arithmetic

Question 29

Advantage of S+M

Answer 29

Easy for humans to do

Question 30

What do positive numbers start with (twos complement)

Answer 30

Always start with 0

Question 31

What do negative numbers start with (twos complement)

Answer 31

Always start with a 1

Question 32

What does the most significant bit represent (twos complement)

Answer 32

Represents a negative number

Question 33

Positive binary number into negative twos complement method

Answer 33

1. Write out the positive version of the number
2. Starting from the right most bit copy each of the digits exactly as they appear up to and including the first 1
3. From this point swap every 1 for a 0 and every 0 for a 1

Question 34

Advantage of twos complement

Answer 34

It is better for arithmetic

Question 35

Define character set

Answer 35

A defined list of characters recognised by the computer hardware and software, with each character being represented by a single nunber

Question 36

ASCII mean

Answer 36

American Standard Code for Information Interchange

Question 37

How many ASCII bits

Answer 37

7

Question 38

UNICODE bits

Answer 38

24 bit character set