Data types

Question 1

Primitive Data Types

Answer 1

“The basic data types provided by a programming language as building blocks. Most languages allow more complicated composite types to be recursively construction starting from basic types. E.g. char, integer, float, Boolean. As an extension a ‘string’ data type is constructed behind the scenes of many char data types.”

Question 2

Integer

Answer 2

“A data type used to store positive and negative whole numbers

Question 3

Real

Answer 3

“A data type used to store an approximation of a real number in a way that can support a trade-off between range and precision. A number is, in general, represented approximately to a fixed number of significant digits and scaled using an exponent.”

Question 4

Floating Point

Answer 4

“A data type used to store an approximation of a real number in a way that can support a trade-off between range and precision. A number is, in general, represented approximately to a fixed number of significant digits and scaled using an exponent.”

Question 5

Character

Answer 5

“A single alphanumeric character or symbol.”

Question 6

String

Answer 6

“A sequence of alphanumeric characters and or symbols. e.g. a word or sentence.”

Question 7

Boolean

Answer 7

“Used to store the logical conditions TRUE / FALSE. Often translated to On/Off, Yes/No etc.”

Question 8

Binary

Answer 8

“Binary describes a numbering scheme in which there are only two possible values for each digit: 0 and 1. The term in computing refers to any digital encoding system in which there are exactly two possible states. E.g. in memory, storage, processing and communications, the 0 and 1 values are sometimes called “low” and “high”, respectively.”

Question 9

Sign and Magnitude

Answer 9

“A method in computing of being able to store negative numbers as string of pure binary digits. It works by turning the MSB into a sign bit, where 0 represents a positive number and 1 represents a negative.”

Question 10

Two’s Complement

Answer 10

“A method in computing of being able to store and represent floating point real numbers (both positive and negative) as a string of pure binary digits. Uses the concepts of two’s complements, mantissa and exponent.”

Question 11

Hexadecimal

Answer 11

“A numerical system of notation which uses 16 rather than 10 as its base. The 16 Hex base digits are 0-9 and the letters A-F.”

Question 12

Denary

Answer 12

“A numerical system of notation which uses 10 as its base. The 10 Decimal base digits are 0-9.”

Question 13

Floating Point Arithmetic

Answer 13

“The mathematical process of performing simply calculations on more than one floating-point number stored in binary notation.”

Question 14

Bitwise Manipulation

Answer 14

“The act of algorithmically manipulating bits or other pieces of data shorter than a word. Programming tasks that require a bit manipulation include low-level device control, error detection and correction algorithms, data compression, encryption algorithms, and optimisation.”

Question 15

Shifts

Answer 15

“An operation that moves the bits held in a register, called the shift register, either to the left or the right. There are three different types of shift: arithmetic shift, logical shift and cyclic shift. They are distinguished by what happens to the bits that are shifted out of the register at one end and what is moved in to fill the vacant space at the other end.”

Question 16

AND

Answer 16

“A logical operator used within a program. AND works by only returning TRUE if both values being compared are TRUE.”

Question 17

OR

Answer 17

“A logical operator used within a program. OR works by returning TRUE as long as either value being compared is TRUE.”

Question 18

XOR

Answer 18

“A logical operator used within a program. XOR stands for exclusive OR. It will return TRUE if the two items being compared are different.”

Question 19

Character Sets

Answer 19

“The set of symbols that may be represented in a computer at a particular time. These symbols, called characters, can be letters, digits, spaces or punctuations marks, the set includes control characters.”

Question 20

ASCII

“America Standard Code for Information Interchange”

Answer 20

A character set devised for early telecommunication systems but proved to be ideal for computer systems. ASCII codes use 7-bits giving 32 control codes and 96 displayable characters (the 8th bit is often used for error checking).”

Question 21

UNICODE

Answer 21

“Standard character set that replaces the need for all the different character sets. It incorporates characters from almost all the world’s languages. It is a 16-bit extension of ASCII.”