4.5: Character Sets & Data Types
Exam Board:
Eduqas / WJEC
Specification:
2020 +
What is a Character Set?
A character set is a table that matches together a character and a binary value.
Character sets are necessary as they allow computers to exchange data.
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Two common character sets are ASCII and Unicode.
ASCII
Unicode
(American Standard Code for Information Interchange)
0100 0001
0100 0010
0100 0011
Uses Binary
128
Tiny Set of Characters
Less Memory Required Per Character
U+0042
U+0055
U+004E
Uses Hexadecimal
137,000+
Large Set of Characters
More Memory Required per Character
What are the different data types?
When programming, variables should be given appropriate data types.
Character
String
Integer
A single character, such as a letter, number or punctuation symbol.
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Examples:
A sequence of characters, including letters, numbers and punctuation.
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Examples:
A whole number.
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Examples:
T
8
?
Harry Waters
14:50pm
Ice Age 4
475
-8432
56732
Real
Boolean
Telephone numbers are always stored as a string, not an integer.
True / False
Yes / No
0 / 1
An answer that only has two possible values.
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Examples:
A decimal number.
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Examples:
65.3
-321.1234
909.135
Be careful with punctuation.
32.10 is a real but £32.10 is a string.
Questo's Questions
4.5 - Character Sets & Data Types:
1. What is a character set and why are they needed? [2]
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2. Describe 3 differences between ASCII and Unicode. [6]
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3. State the 5 different data types. [5]
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4. State which data type is most suitable for the following variables:
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a. Age [1]
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b. Surname [1]
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c. Height (in metres) [1]
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d. First Initial [1]
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e. Phone number [1]
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f. Right-Handed? [1]