1.4.1 Data Types

Question 1

Convert this binary to denary in two’s complement: 01000011

Answer 1

67

Question 2

Convert this binary to denary in two’s complement: 10111100

Answer 2

-68

Question 3

Convert this denary to binary in two’s complement: -47

Answer 3

1101 0000

Question 4

Convert this denary to binary in two’s complement: 86

Answer 4

0101 0110

Question 5

How many available values are there for each digit in hexadecimal?

Answer 5

16

Question 6

Convert the unsigned binary number 11110000 to hexadecimal

Answer 6

F0

Question 7

Common Data Types (5)

Answer 7

Character. Real (float). Integer. Boolean. String.

Question 8

What is a pointer? (2)

Answer 8

A pointer is a built-in data type in some low-level languages. It will hold the address of a value or object located in computer memory.

Question 9

Memory requirements of each data type (5)

Answer 9

Character (4 bytes), String (4 bytes for each character), Boolean (1 bit), Integer (4 bytes), Real (4 bytes).

Question 10

What are the rules of binary addition?

Answer 10

0+0=0. 1+0=1. 0+1=1. 1+1=0 and carry 1. 1+1+1=1 and carry 1.

Question 11

How do we represent signed binary integers?

Answer 11

The most significant bit becomes a sign digit. 0 represents positive. 1 represents negative.

Question 12

How do we represent binary integers in two’s complement?

Answer 12

The most significant bit becomes the neative of that number.

Question 13

How do you add 2 floating point numbers? [3]

Answer 13

1. Normalise both numbers 2. Equalise the exponents by increasing the smaller one to match the larger one 3. Add the mantissas

Question 14

How do you subtract 2 floating point numbers? [5]

Answer 14

1. Normalise both numbers 2. Equalise the exponents by increasing the smaller one to match the larger one 3. Find the two’s complement negative value of second number 4. Subtract by adding the two mantissas 5. Normalise the result

Question 15

What happens during a left shift? [3]

Answer 15

All the bits in the number are shifted to the left by a specified number of places [1] For every 1-bit shift: The most significant bit is discarded [1] A 0 is put into the empty space on the right [1]

Question 16

What happens during a right shift? [3]

Answer 16

All the bits in the number are shifted to the right by a specified number of places [1] For every 1-bit shift: The least significant bit is discarded [1] A 0 is put into the empty space on the right [1]

Question 17

Why can’t logical shifts be applied to signed numbers? [1]

Answer 17

The sign bit must not be shifted [1]

Question 18

What is a 1-bit left shift equivalent to? [1]

Answer 18

Multiplying by 2 [1]

Question 19

What is a 1-bit right shift equivalent to? [1]

Answer 19

Dividing by 2 [1]

Question 20

What is the difference between an arithmetic and logical shift? [1]

Answer 20

The most significant bit is not shifted during an arithmetic shift [1]

Question 21

In what case of an arithmetic shift are the empty places padded with a 1? [1]

Answer 21

Right shift of a negative number [1]

Question 22

What is a cyclical shift? [1]

Answer 22

A shift where the discarded space is placed into the empty space on the other side of the number [1]

Question 23

Denary to Binary [1]

Answer 23

Divide number by 2, account for result and remainder. Repeat until 0. [1]

Question 24

Binary to Hexadecimal [1]

Answer 24

Convert each group of 4 bits into 1 denary digit [1]

Question 25

Hexadecimal into Binary [1]

Answer 25

Convert each digit into denary and convert into 4 bits [1]