1. Definition
2. When to use
3. How to Achieve
4. Difference between Inheritance and Abstraction
5. Difference between Encapsulation and Abstraction

1. Definition

Abstraction is the process of concealing the intricate internal workings of an object or system while exposing a simplified interface that highlights only the relevant aspects necessary for interaction. This allows users or developers to work with a system at a higher level, focusing on what the system does rather than how it achieves its functionality.

Key Points

• Hides Complexity: Abstracts away the internal details, allowing users to interact with a system through a straightforward interface.
• Simplified Interface: Provides a clear, user-friendly interface that focuses on the essential features.
• Modular Design: Encourages the development of modular and reusable components by separating concerns and reducing dependencies.

In programming, this concept is applied through techniques such as:

• Abstract Classes: Classes that cannot be instantiated directly but can be subclassed to provide a common interface for related classes.
• Interfaces/Protocols: Define a set of methods or properties that conforming classes or structs must implement, without specifying how these methods are implemented.

// Protocol defining an abstract concept
protocol Shape {
    func area() -> Double
    func perimeter() -> Double
}

// Concrete class implementing the protocol
class Rectangle: Shape {
    var width: Double
    var height: Double
    
    init(width: Double, height: Double) {
        self.width = width
        self.height = height
    }
    
    func area() -> Double {
        return width * height
    }
    
    func perimeter() -> Double {
        return 2 * (width + height)
    }
}

2. When to use