What Are Data Structures and Why Are They Useful?

TL;DR

A data structure is a systematic way to organize data so it can be used efficiently in terms of time and space. Arrays can manage sequences and bitmap pixels, stacks can support undo and redo operations, and graphs can represent friendship connections on social networking sites.

Transcript

Welcome all. From this presentation onwards, we will study a new subject that is, data structures. And in this presentation, I will introduce what data structure is, and some real life examples of data structures. So, let's get started. Before understanding what data structure is, Let's first try to understand what is data. This is a prerequisite.... Read More

Key Insights

• Data is a collection of quantities, characters, or symbols on which computer operations can be performed. It may be stored, transmitted as electrical signals, or recorded using magnetic, optical, or mechanical media, making it the raw material handled by computer systems.
• Information is meaningful or processed data that has been arranged systematically. A collection of characters may initially be unreadable, but processing it, such as reversing its character order, can reveal an understandable message and transform the raw data into information.
• A data structure is a systematic way to organize data so it can be used efficiently. Its purpose is to arrange and manage data appropriately, making meaningful information easier to obtain and the stored data easier to use whenever required.
• Data-structure efficiency concerns both time and space. Organizing data is not only about preserving values, but also about enabling those values to be stored, accessed, and used efficiently according to the needs of a computer program.
• An array is a sequential data structure that can hold collections of symbols, characters, integers, or floating-point values. One array can replace many separate variables of the same type, such as when storing 100 integers or the characters in a string.
• Stacks support undo and redo by exposing the most recently stored operation at the top. Undo pops the top item from the undo stack and places it into the redo stack, while redo moves that item back into the undo stack.
• A bitmap image can be represented by a two-dimensional array containing pixel information. Each pixel is assigned a color, and the pixels are arranged in a systematic pattern that forms the complete image, such as the demonstrated 37 by 40 pixel example.
• A graph can represent friendship information on a social networking site. People are represented as connected entities, and an edge records a friendship between two people. When two people are not friends, no edge is placed between them.

Questions & Answers

Q: What is data in computer science?

Data consists of quantities, characters, or symbols on which a computer can perform operations. It may be stored, transmitted in the form of electrical signals, and recorded on magnetic, optical, or mechanical media. Numbers used in an arithmetic operation qualify as data because they are quantities that can be processed, stored, and transmitted.

Q: What is the difference between data and information?

Data is a raw collection of quantities, characters, or symbols, while information is data that has been processed or arranged so that it carries understandable meaning. For example, an unreadable sequence of characters remains data. If reversing that sequence reveals a readable statement, the processing has converted the data into meaningful information.

Q: What is a data structure?

A data structure is a systematic way to organize data so it can be used efficiently. It provides an appropriate method for arranging and managing data, allowing meaningful information to be produced and stored values to be used when required. The efficiency of a data structure is considered in terms of both time and space.

Q: Why are data structures important?

Data structures are important because data must be managed and arranged appropriately before it can be used efficiently or turned into meaningful information. They provide systematic organization for storage and access, with attention to time and space efficiency. Their practical uses include managing arrays, implementing undo and redo, storing bitmap images, and representing friendships.

Q: Why is an array considered a data structure?

An array is considered a data structure because it organizes a sequence or collection of values in a systematic, sequential manner. It can store symbols, characters, integers, or floating-point values. Instead of creating 100 separate variables for 100 integers, one array can hold them together and make the collection easier to manage and access.

Q: How do stacks implement undo and redo operations?

Undo and redo can be implemented with two stacks that store entered operations. Pressing undo selects the top item from the undo stack, pops it out, and places it into the redo stack. Pressing redo selects that item from the redo stack, pops it, and pushes it back into the undo stack, restoring the operation.

Q: How does an array store a bitmap image?

A bitmap image can be stored in a two-dimensional array because it consists of tiny dots called pixels. Each pixel is a small square assigned a color. The array stores the color information for each pixel and arranges those pixels in a systematic pattern. The example uses a 37 by 40 array to form an image.

Q: How can a graph represent friendships on a social network?

A graph represents friendship information by recording connections between people. An edge between two people indicates that they are friends, while the absence of an edge indicates that no friendship is recorded between them. This structure can show, for example, that one person is connected to multiple friends while remaining unconnected to someone else.

Summary & Key Takeaways

• Data consists of quantities, characters, or symbols on which a computer performs operations. It can be stored, transmitted as electrical signals, and recorded on magnetic, optical, or mechanical media. When raw data is processed and systematically arranged so that meaning can be extracted from it, the result is called information.

• A data structure organizes and manages data so it can be used efficiently in terms of time and space. An array is a classical example because it stores a sequence of related values under one structure, avoiding the need to create a separate variable for every integer or character in a string.

• Common software features demonstrate why structured data matters. Undo and redo can use separate stacks to move the most recent operation between histories. Bitmap images can use two-dimensional arrays to organize pixel colors, while social networking sites can use graphs whose edges represent friendship relationships between connected people.