37 Questions
What is the purpose of constructors in abstract data types?
To build the abstract data type
What information does the city object hold?
The city's name, latitude, and longitude
What is the purpose of selectors in abstract data types?
To retrieve information from the data type
How do you create a city object?
Using a function like city = makecity (name, lat, lon)
Who defines the functions for the end user?
Someone else
What is assumed about the functions in the abstract data type?
The end user doesn't know how they were implemented
What is the role of constructors and selectors in abstract data types?
Constructors build the data type, selectors retrieve information
What is the abstraction level of the city object?
Abstract data type
What is the purpose of naming the parts of a multi-item object?
To make it easier to access each item
What is the main difference between a list and a multi-item object like a Person?
A list allows direct access to each item, while a Person object does not
What is an advantage of using named parts in a multi-item object?
It makes the code more readable
What is the purpose of the 'id' attribute in the Person object?
To store a unique identifier for the person
How is the Person object represented pictorially?
As a diagram with named parts
What is the main benefit of using a multi-item object like a Person?
It allows for more organized and structured data
What is the purpose of the constructor function makecity()?
To create an object of the city
What do the functions getlat() and getlon() retrieve from the city object?
The city's latitude and longitude
What is the purpose of the distance() function?
To compute the distance between two city objects
What does the := symbol represent in the pseudo code?
An assignment operator
What is the term used to describe the functions getlat() and getlon()?
Selectors
What is the formula used to compute the distance between two city objects?
(lt1 - lt2)**2 + (lg1 - lg2)**2)**1/2
What is the purpose of the lt and lg variables in the distance() function?
To store the city's latitude and longitude
What is the data type of the city object?
Not specified in the pseudo code
What is the primary goal of data abstraction?
To define an abstract data type and separate it from its representation
What is a key component of an abstract data type (ADT)?
A collection of constructors and selectors
What is the purpose of selectors in an abstract data type?
To extract individual pieces of information from an object
What is the relationship between the part of a program that operates on abstract data and the part that defines a concrete representation?
They are connected by a small set of functions that implement abstract data in terms of the concrete representation
What is a rational number an example of?
A sub-class of real numbers
What is the purpose of the example of rational numbers in the context of data abstraction?
To illustrate the technique of data abstraction
What is the result of constructors in an abstract data type?
An object that bundles different pieces of information
What is the role of a small set of functions in data abstraction?
To implement abstract data in terms of the concrete representation
What is an Abstract Data Type (ADT)?
A type that defines a set of values and operations
What does the definition of an Abstract Data Type (ADT) specify?
What operations will be performed
What is the process of providing only the essentials and hiding the details called?
Abstraction
What is the main difference between a concrete and abstract implementation?
The level of abstraction
What is an example of a concept related to Abstract Data Types?
Data Structures
What is the purpose of Abstraction in Data Structures?
To hide the implementation details
What is the benefit of using Abstract Data Types (ADTs)?
Implementation independence
Study Notes
Data Abstraction
- Data Abstraction is a process of providing only the essential features and hiding the details.
- It gives an implementation-independent view.
Abstract Data Types (ADT)
- ADT is a type (or class) for objects whose behavior is defined by a set of values and a set of operations.
- The definition of ADT only mentions what operations are to be performed, but not how these operations will be implemented.
- It does not specify how data will be organized in memory and what algorithms will be used for implementing the operations.
Difference between Concrete and Abstract Implementation
- Concrete implementation is implementation-dependent.
- Abstract implementation is implementation-independent.
Constructors and Selectors
Constructors
- Constructors are functions that build the abstract data type.
- They create an object, bundling together different pieces of information.
Selectors
- Selectors are functions that retrieve information from the data type.
- They extract individual pieces of information from the object.
Example: City Abstract Data Type
- The city object will hold the city's name, and its latitude and longitude.
- Constructors:
city = makecity (name, lat, lon) - Selectors:
getname(city),getlat(city),getlon(city)
Data Abstraction in Programming
- Data abstraction is supported by defining an abstract data type (ADT), and constructors and selectors.
- The two parts of a program are: the part that operates on abstract data, and the part that defines a concrete representation, connected by a small set of functions that implement abstract data in terms of the concrete representation.
Learn about abstract data types and abstraction in programming. Understand the concept of ADT and its importance in programming.
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