To facilitate data abstraction, you will need to create two types of functions: constructors and selectors.

There can be different ways to implement an ADT, for example, the list ADT can be implemented using singly linked list or doubly linked list. Similarly, stack ADT and queue ADT can be implemented using lists.

The process of providing only the essentials and hiding the details is known as abstraction.

Abstract Data Type is a type for objects whose behaviour is defined by a set of values and a set of operations.

Modularity means splitting a program into many modules. Abstraction provides modularity.

Data abstraction is a powerful concept in computer science that allows programmers to treat code as objects.

(i) The elements of a list can be accessed in two ways.
(ii) The first way is via multiple assignment and the second method is by the element selection operator

Person is referred to as a class or a type, while p1 is referred to as an object or an instance.

(i) A class defines a data abstraction by grouping related data items. A class is not just data, it has functions defined within it.
(ii) Functions are subordinate to the class because their job is to do things with the data of the class.

rational(n, d):
return [n, d]
numer(x):
return x[0]
denom(x):
return x[1]

(i) A pair is a compound data type that holds two other pieces of data. The two ways of representing the pair data type.
(ii) The first way is using List construct and the second way to implement pairs is with the tuple construct.

(i) To implement the concrete level of data abstraction, languages like Python provides a compound structure called Pair which is made up of list or Tuple.
(ii) The first way to implement pairs is with the List construct

The pseudo code for the representation of the rational number using the above constructor and selector is component
x,y:=8,3
rational(n,d)
numer(x)/numer(y)
- - output: 2.6666666666666665

(i) Selector
(ii) Constructor

(i) There can be different ways to implement an ADT, for example, the, List ADT can be implemented using singly linked list or doubly linked list.
(ii) Similarly, stack ADT and Queue ADT can be implemented using lists