1.4.1 - Data Types

Question 1

What are the five primitive data types?

Answer 1

Integer, Real/Floating Point, Character, String, Boolean.

Question 2

What is an Integer data type?

Answer 2

A whole number, including zero and negatives, without a fractional part.

Question 3

What is a Real/Floating Point data type?

Answer 3

A positive or negative number that can have a fractional part.

Question 4

What is a Character data type?

Answer 4

A single symbol, including letters, numbers, and symbols.

Question 5

What is a String data type?

Answer 5

A collection of characters, used for storing text.

Question 6

What is a Boolean data type?

Answer 6

A data type restricted to the values True and False.

Question 7

How are positive integers represented in binary?

Answer 7

Using base-2, where each bit represents a power of two.

Question 8

What is the least significant bit (LSB)?

Answer 8

The rightmost bit in a binary number, representing 2^0 (1).

Question 9

What is the most significant bit (MSB)?

Answer 9

The leftmost bit in a binary number, representing the highest power of two.

Question 10

What is a byte?

Answer 10

A group of 8 bits.

Question 11

What is a nybble?

Answer 11

Half a byte; a group of 4 bits.

Question 12

Convert the binary number 1101 to decimal.

Answer 12

(81)+(41)+(20)+(11) = 13

Question 13

Convert the decimal number 47 to binary.

Answer 13

101111 (or 00101111 as a byte)

Question 14

What are the four rules for binary addition?

Answer 14

0+0+0=0; 0+0+1=1; 0+1+1=10; 1+1+1=11

Question 15

Add the binary numbers 1011 and 1110.

Answer 15

1011 + 1110 = 11001

Question 16

What is Sign Magnitude representation?

Answer 16

A method where the leftmost bit indicates the sign (0=positive, 1=negative).

Question 17

How is -173 represented in 9-bit Sign Magnitude if 173 is 10101101?

Answer 17

110101101 (1 added for negative sign)

Question 18

What is Two’s Complement?

Answer 18

A method where the MSB has a negative weight, simplifying arithmetic.

Question 19

How do you find the Two’s Complement of a number?

Answer 19

Flip all the bits and add 1.

Question 20

What is the 8-bit Two’s Complement of 7?

Answer 20

00000111 -> 11111000 -> 11111001

Question 21

Subtract 12 from 8 using 5-bit Two’s Complement.

Answer 21

8 (01000) + (-12 = 10100) = 11100 (which is -4)

Question 22

What base is hexadecimal?

Answer 22

Base-16.

Question 23

What digits and letters are used in hexadecimal?

Answer 23

0-9 and A-F (where A=10, B=11, …, F=15).

Question 24

Convert the hexadecimal number 4E7F to decimal.

Answer 24

(44096)+(14256)+(716)+(151) = 20095

Question 25

Convert the hexadecimal number B2 to binary.

Answer 25

B (11 -> 1011), 2 (2 -> 0010) -> 10110010

Question 26

Convert the hexadecimal number 4C3 to decimal.

Answer 26

(4*256)+(12*16)+(3*1) = 1219

Question 27

What are the two parts of a floating point number?

Answer 27

Mantissa and Exponent.

Question 28

What is the purpose of normalisation in floating point?

Answer 28

To maximise precision by ensuring the mantissa starts with 01 (positive) or 10 (negative).

Question 29

How do you add two floating point numbers?

Answer 29

Make exponents the same, add mantissas, then normalise the result.

Question 30

How do you subtract two floating point numbers?

Answer 30

Make exponents the same, convert subtrahend to two's complement, add, then normalise.

Question 31

What is a logical shift left?

Answer 31

Moving all bits left, adding trailing zeros; equivalent to multiplication by 2^n.

Question 32

What is the result of a logical shift left by 3 on 10010110?

Answer 32

10010110000

Question 33

What is a bitmask?

Answer 33

A binary pattern used with a logic gate (AND, OR, XOR) to manipulate specific bits.

Question 34

What does an AND mask do?

Answer 34

Returns 1 only if both corresponding bits are 1; used to 'extract' bits.

Question 35

What does an OR mask do?

Answer 35

Returns 1 if at least one corresponding bit is 1; used to 'set' bits.

Question 36

What does an XOR mask do?

Answer 36

Returns 1 if corresponding bits are different; used to 'toggle' bits.

Question 37

What is a character set?

Answer 37

A published collection of codes and their corresponding characters.

Question 38

What is ASCII?

Answer 38

American Standard Code for Information Interchange; uses 7 bits for 128 characters.

Question 39

What is the main limitation of ASCII?

Answer 39

Limited to 128 characters, insufficient for many languages and symbols.

Question 40

What is Unicode?

Answer 40

A character set using a variable number of bits, supporting over 1 million characters.

Question 41

What is the key advantage of Unicode over ASCII?

Answer 41

It can represent a vast range of characters from many languages and symbols.