Computer Science AS OCR
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1-1-structure-and-function-of-the-processor as5 主题
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1-2-types-of-processor as3 主题
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1-3-input-output-and-storage as2 主题
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2-1-systems-software as8 主题
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2-3-software-development as5 主题
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2-4-types-of-programming-language as4 主题
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3-1-compression-encryption-and-hashing as3 主题
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3-2-databases as3 主题
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3-3-networks as8 主题
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3-4-web-technologies as13 主题
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html as
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css as
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css-styling as
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javascript as
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variables-and-constants-in-javascript as
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outputs-in-javascript as
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selection-in-javascript- as
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for-loops-in-javascript- as
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while-loops-in-javascript- as
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strings-in-javascript- as
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operators-in-javascript- as
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nested-statements-in-javascript as
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functions-and-procedures-in-javascript as
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html as
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4-1-data-types as8 主题
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4-2-data-structures as4 主题
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4-3-boolean-algebra as1 主题
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5-1-computing-related-legislation as4 主题
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5-2-moral-and-ethical-issues as9 主题
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6-1-thinking-abstractly as3 主题
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6-2-thinking-ahead as1 主题
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6-3-thinking-procedurally as3 主题
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6-4-thinking-logically as2 主题
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6-5-thinking-concurrently as2 主题
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7-1-programming-techniques as9 主题
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8-1-standard-algorithms-and-big-o-notation as8 主题
primitive-data-types as
Exam code:H046
Primitive Data Types
What are Data Types?
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A data type is a classification of data into groups according to the kind of data they represent
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Computers use different data types to represent different types of data in a program
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The basic data types include:
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Integer: used to represent whole numbers, either positive or negative
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Examples: 10, -5, 0
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Real: used to represent numbers with a fractional part, either positive or negative
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Examples: 3.14, -2.5, 0.0
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Char: used to represent a single character such as a letter, digit or symbol
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Examples: ‘a’, ‘B’, ‘5’, ‘$’
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String: used to represent a sequence of characters
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Examples: “Hello World”, “1234”, “@#$%”
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Boolean: used to represent true or false values
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Examples: True, False
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It is important to choose the correct data type for a given situation to ensure accuracy and efficiency in the program
Casting
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Casting is when you convert one data type to another data type
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When a user enters data into a program, this will more than likely be in a string format
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It’s essential to convert some of this string data to a numerical format where possible
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For example, you may want to perform calculations on age-related data to determine if someone is eligible to vote
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Some programming languages can’t execute numerical comparisons on text data, making this transformation crucial
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For example if you had “12” stored as a string and you wanted to know if this value was below 20
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Therefore, the string value of “12” will need to be cast as an integer to allow the comparison to take place
Python example
int_value = int("123") // converts the string "123" to 123
float_value = float("3.14") // converts the string "3.14" to 3.14
Java example
int intValue = Integer.parseInt("123"); // converts the string "123" to 123
double doubleValue = Double.parseDouble("3.14"); // converts the string "3.14" to 3.14
Casting between data types
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Conversion |
Example |
Output |
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From Integer to Real |
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From Real to Integer |
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From String to Integer |
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From Integer to String |
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From Boolean to String |
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From String to Boolean |
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Worked Example
You are tasked with designing a program for a bookstore.
The program should be able to store each piece of information given in table.
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Book Detail |
Recommended Data Type |
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The book’s title |
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The number of pages the book has |
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The price of the book |
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Whether the book is currently in stock or not |
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The average rating given by customers which ranges from 1 to 5 |
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Complete the table by identifying a suitable data type for each piece of information in the table.
5 marks
Answer:
Answer that gets full marks
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Book Detail |
Recommended Data Type |
|---|---|
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The book’s title |
String |
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The number of pages the book has |
Integer |
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The price of the book |
Float |
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Whether the book is currently in stock or not |
Boolean |
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The average rating given by customers ranging from 1 to 5 |
Float |
Responses