Data Types vs. Abstract Data Types

Summary

Highlights

• Understanding the domain and operations of basic data types like integer and float. 📊
• User-defined data types allow customization beyond language-specified types. ⚙️
• Abstract Data Types function as interfaces, obscuring the implementation details. 🔒
• Stacks, a type of ADT, showcase flexibility and abstraction by allowing different internal implementations. 📚
• ADTs provide a crucial separation of concerns, enhancing program flexibility and user ease. 🌐

Key Takeaways

• Data types specify domains and operations, like integers allowing arithmetic. 🧮
• User-defined data types are created by users, giving control over operations and values. 👩‍💻
• Abstract Data Types (ADTs) hide implementation details, offering a 'black box' experience. 📦
• Stacks are a classic example of ADTs, demonstrating abstraction through various implementations. 🥞
• ADTs facilitate seamless changes in implementation, keeping client programs unaffected. 🔄

Overview

Chapters

• 00:00 - 02:30: Introduction to Data Types In this chapter, the concept of data types and their significance in understanding data structures is explored. A data type is not only about the domain of values it defines but also specifies the operations allowed on those values. For instance, an integer data type permits arithmetic and bitwise operations, while a float data type supports arithmetic operations but not bitwise or mod operations. This distinction is crucial in comprehending how data types function within different programming paradigms.
• 02:30 - 05:00: User Defined Data Types The chapter explores user-defined data types and abstract data types (ADTs). It explains that user-defined data types are created when we form a new type, such as a 'point'. Further, the chapter delves into ADTs, highlighting that they define operations on values through functions without revealing the inner workings of these functions. For instance, a stack is introduced as a typical ADT, characterized by sequentially ordered elements of the same type, with operations like initialize, push, pop, and checks for fullness or emptiness. These operations are outlined but not specified in detail, emphasizing the concept of abstraction. ADTs are portrayed as 'black boxes' that conceal their implementation details, which is crucial for maintaining a focus on what operations can be performed, rather than how they are executed. The chapter also touches on the multiple ways to implement an ADT, using examples like arrays or linked lists for implementing a stack structure. The information underscores the flexibility and abstraction significance in designing complex data structures.
• 05:00 - 07:30: Abstract Data Types The chapter "Abstract Data Types" introduces the concept of Abstract Data Types (ADTs) and emphasizes their importance in programming.
• 07:30 - 10:00: Importance of ADTs The chapter titled 'Importance of ADTs' highlights the significance of abstract data types (ADTs) in programming. It is a concise presentation that emphasizes how ADTs serve as a useful concept in organizing and managing data in a systematic way. The speaker wraps up the discussion by thanking the audience for their attention.

Data Types vs. Abstract Data Types Transcription

• Segment 1: 00:00 - 02:30 In our journey towards learning data structures, we first have to understand the difference between data types and abstract data types. So, let's get started. What is a data type? We have already discussed what a data type is in our C programming lectures. But let's discuss it one more time because there are certain points which I haven't discussed there. There are two important things, that I haven't told you about data types. Although there is one point which is already clear. But there is more important point which I haven't told about data type. First is, it defines a certain domain of values. You already know that a data type defines a certain domain of values. Right? But there is one more important point which says that, it defines operations allowed on those values. So, not only it is defining certain domain of values but it also defines what operations are allowed on those values. For example, we can think of integer type. Here, we can take only integer values. You already know that integer allows only integer values. Right? But the operations allowed are addition, subtraction, multiplication, bitwise operations et cetera. We can perform almost every operation with integer type. For the sake of understanding, let's take another type, that is float type. It takes only floating point values. We already know that, the domain of values allowed in the case of float type are only floating point values. But the operations which we can perform on float types are addition, subtraction, multiplication, division but we cannot perform bitwise and mod operations on them. This should be well noted. So, it is clearly understandable that a data type not only defines a certain domain of values, but is also defines operations allowed on those values. Right? Now let's discuss what is a user defined data type. Before moving on to abstract data type, we should understand what is a user defined data type. In contrast to primitive data types, there is a concept of user defined data types.
• Segment 2: 00:00 - 02:30 You already know primitive data types like integer, character, float. Right? But there is a concept of user defined data type which we should also know. The operations and values of user defined data types are not specified in the language itself, but is specified by the user. Here the user is defining the operations as well as the values. It is not pre defined in the language itself. Okay. Now, here are the examples. Structure, union and enumeration which we have already discussed. By defining structures, we are defining our own type by combining other data types. By using structures, we are defining our own type, by combining other primitive types. For example, here in this case, we have combined these two integers
• Segment 3: 02:30 - 05:00 to form a new type, that is point. So, it's a user defined data type. This is our understanding about user defined data types. Now, let's try to understand what are abstract data types. ADTs or Abstract data types are like user defined data types which defines operations on values using functions without specifying what is there inside the function and how the operations are performed. First of all, we are defining operations, that is true. But we are defining operations on values, that is also true, using functions. It should be well noted that, we are defining operations using functions, without specifying what is there inside the function. And we are not specifying anything inside, what is there inside the function. Okay, and how the operations are performed. Let's take an example of a stack ADT. A stack consists of elements of same type arranged in a sequential order. So, what types of elements are allowed in a stack? The elements of same type. And that too, they are arranged in a sequential order, we already know that right? Now, the operations allowed on them could be initialize- we can define an initialize function which initializes the stack to be empty actually. We can perform a push operation that is, insert an element into the stack. We can perform pop operation that is, delete an element from the stack. We can check is stack empty or we can check is stack full. So, these are the operations which we can define and we can perform on stack. These are functions, as you can see. Here, we are specifying function but we are not saying anything, how they can be implemented. We are just specifying them. That is called abstract data type. We know that, what type of elements are allowed and we also know that what operations we can perform, but we don't know what is there inside. Okay. Think of ADT as a black box which hides the inner structure and design of the data type from the user. We can think of it like, it hides all the implementation details from us. This is very important which we will understand later.
• Segment 4: 02:30 - 05:00 There are multiple ways to implement an ADT. Let me tell you, this is very important. There are multiple ways to implement an ADT. For example, a stack ADT can be implemented using arrays or linked lists. It should be well noted that stack itself is a data structure, we can implement this data structure using other data structures like arrays or linked lists. Okay. So, a stack ADT, which we know is right now is a skeleton, can be implemented using arrays or linked lists.
• Segment 5: 05:00 - 07:30 Now, the question that immediately arises that why do we even need ADTs? Why do we need skeletons? Why can't we simply implement things, you know display it to the user. Why ADT? Before moving further, we should understand some terminology. The program which uses data structure is called a client program. You should note this very clearly, that the program which uses data structure is called a client program. It has access to the ADT that is the interface, nothing else. Just abstract. And the program which implements the data structure is known as the implementation. So, we have two programs, one is client program, the other one is implementation. Implementation is the one which implements the data structure and the client program is the one which just uses the interface, that is the outside details, nothing inside. Okay. Now, let's discuss the advantage. Let's say, if someone wants to use the stack in the program, then he can simply use push and pop operations without knowing its implementation. A user doesn't have to worry about how the operations are performed. Okay. If someone wants to use the stack program, we know that, program which uses the data structure is called the client program. It has access to the interface only and nothing inside. So, he can simply use push and pop operations without knowing its implementation. Apart from this, if in future, the implementation of stack is changed from array to linked list, let's say, previously the stack was implemented using arrays, right? But know, let's say it is changed to linked list. Then the client program will work in the same way without being affected. There is nothing to discuss with client program. Client program has nothing to do with it. It can simply use the interface, without knowing what is going on inside. So, if the implementation is changed from array to linked list, nothing will be affected in the client program. This is one of the biggest advantages of using abstract data types. Now, it should be clear that, why we are using it.
• Segment 6: 05:00 - 07:30 Because, with the help of abstract data types, we are actually separating the two worlds. We are just providing the user, an interface. The rest of the details, the implementation part is done in the back end. User doesn't have to worry about it. The implementation can go on without affecting the client program. That is why, the need of abstract data type came. Now, here is the conclusion of this lecture. Abstract data type provides abstraction. We should understand this, that abstract data type provides abstraction which means hiding details from the user and it is very important because user doesn't bother about how that particular thing is implemented. He just have to use that thing. That's it. So, this separation is required.
• Segment 7: 07:30 - 10:00 That's why abstract data type is very useful concept. Okay friends, this is it for now. Thank you for watching this presentation.