What are the differences between functions and methods in Swift?

In Swift, functions and methods are both reusable chunks of code that perform specific tasks, but they have distinct differences in terms of their association with types and how they are called.

Functions

• Definition: Functions are independent pieces of code that perform a specific task. They are not associated with any particular type (class, struct, or enum).
• Syntax: Functions are defined using the func keyword followed by the function name, parameters, and return type.
• Calling: Functions are called by their name directly and do not require an instance of a type.
• Scope: Functions can be defined globally, outside of any type.
• Example:

  func sayHello() {
      print("Hello, World!")
  }
  sayHello() // Output: Hello, World!

Methods

• Definition: Methods are functions that are associated with a specific type (class, struct, or enum). They can be either instance methods or type methods.
• Syntax: Methods are also defined using the func keyword, but they are defined within the context of a type.
• Calling: Methods are called on an instance of the type (for instance methods) or on the type itself (for type methods).
• Scope: Methods must be defined within a type.
• Instance Methods: These methods operate on instances of the type and have access to the instance's properties and other methods.
• Type Methods: These methods are associated with the type itself and are defined using the static or class keyword.
• Example:

  struct Car {
      var speed: Int
      
      // Instance method
      func drive() {
          print("Driving at \(speed) MPH")
      }
      
      // Type method
      static func make() -> Car {
          return Car(speed: 0)
      }
  }
  
  let myCar = Car(speed: 60)
  myCar.drive() // Output: Driving at 60 MPH
  let newCar = Car.make()

Key Differences

• Association: Functions are not associated with any type, whereas methods are always associated with a type.
• Calling Context: Functions are called independently, while methods are called on instances or types.
• Access to self: Methods have access to the self keyword, which refers to the instance of the type they belong to. Functions do not have this conte...