Data Structures
Overview
Write a program that stores one exam mark and you need one variable. Write one that stores thirty and you do not need thirty variables, because thirty variables cannot be looped over, cannot be sorted, and cannot be passed to a subroutine in one piece. What you need is a single name that holds all thirty and a number that says which one you mean. That is an array, and it is the reason the loop you met earlier in this course is useful at all.
This lesson covers the concept of a data structure and the two the specification names: arrays, in one and two dimensions, and records. Arrays hold many things of the same kind under one name; records hold several different things about one subject. You will learn to use each of them in the design of solutions to simple problems, to combine them into an array of records, and to say why a particular structure suits a particular problem, which is the form the exam question takes.
Objectives
- Understand the concept of data structures.
- Use arrays (or equivalent) in the design of solutions to simple problems.
- Use records (or equivalent) in the design of solutions to simple problems.
Mind map
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Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Data Structures. 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.
- An array holds 15 items. What is the index of the last item? A. 0 B. 14 C. 15 D. 16 Answer: B
- Which statement about an array is correct? A. Its items may have different data types B. Its items are reached by a field name C. All of its items have the same data type D. It can only hold numbers Answer: C
- A two dimensional array Grid has 6 rows and 9 columns. How many elements does it have? A. 15 B. 45 C. 54 D. 69 Answer: C
- Which structure is most appropriate for storing a name, an age and a Boolean about one person? A. A one dimensional array B. A two dimensional array C. A record D. A string Answer: C
- In a one dimensional array holding a grid of width 5, which expression gives the index of the element in row 3, column 2? A. 3 + 2 B. 3 * 5 + 2 C. 3 * 2 + 5 D. 5 * 2 + 3 Answer: B
Work through these questions in the app
Work through these questions in the app
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