Data Types
Overview
Everything inside a computer is a pattern of bits, and a pattern of bits on its own means nothing whatever. The same eight bits, 01000001, are the number 65, the letter A, one pixel of a photograph and part of a machine instruction, depending entirely on what the machine has been told the pattern is for. That instruction is the data type, and without it a computer cannot tell an amount of money from a name.
This lesson covers the five types the specification names: integer, real, Boolean, character and string. You will learn what each one holds, what operations each one supports, and how to choose between them for a given piece of information, which is the form the exam question almost always takes. You will also learn two distinctions that catch people out every year: why a whole number stored as a real is not the same thing as an integer, and why a telephone number is a string.
Objectives
- Understand the concept of a data type.
- Understand and use the following appropriately:
- integer
- real
- Boolean
- character
- string.
Mind map
This topic is mapped out so you can see how the ideas connect.
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Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Data Types. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Which data type should be used to store whether a light is switched on? A. Boolean B. Character C. Integer D. String Answer: A
- Which value could be stored in a variable of type integer? A. 4.0 B. -17 C. False D. seventeen Answer: B
- A postcode such as 0X4 2AB is to be stored. Which is the most appropriate data type? A. Boolean B. Character C. Integer D. String Answer: D
- Which statement about the character type and the string type is correct? A. A character can hold any number of symbols B. A string must contain at least one character C. A character holds exactly one symbol and a string holds any number D. Characters and strings are stored identically in all languages Answer: C
- A program reads 8 and 3 from the keyboard and outputs 83 instead of 11. What is the most likely cause? A. The values were stored as strings and joined rather than added B. The values were stored as Booleans C. Whole-number division was used D. The variables were declared as reals Answer: A
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Work through these questions in the app
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