Structures and Classes

In Swift, structures and classes are used to define custom data types. They allow you to encapsulate properties and methods together to create reusable and modular code. Let's explore the differences between structures and classes:

Structures

Structures in Swift are value types. When you create an instance of a structure, it is copied and assigned to a new variable or constant. Modifying the copied instance does not affect the original instance. Here's an example:

  struct Person {
    var name: String
    var age: Int
  }

  var person1 = Person(name: "John", age: 25)
  var person2 = person1

  person2.name = "Alice"

  document.write(person1.name)  // Output: John
  document.write(person2.name)  // Output: Alice
  

Classes

Classes in Swift are reference types. When you create an instance of a class, it is assigned by reference. Multiple variables or constants can refer to the same instance. Modifying the instance through one reference affects all other references to that instance. Here's an example:

  class Car {
    var brand: String
    var color: String

    init(brand: String, color: String) {
      self.brand = brand
      self.color = color
    }
  }

  var car1 = Car(brand: "BMW", color: "Blue")
  var car2 = car1

  car2.brand = "Mercedes"

  document.write(car1.brand)  // Output: Mercedes
  document.write(car2.brand)  // Output: Mercedes
  

Choosing Between Structures and Classes

When deciding whether to use a structure or a class, consider the following:

• Use structures when you need lightweight data types or when you want to take advantage of value semantics.
• Use classes when you need reference semantics, inheritance, or the ability to create shared mutable state.

Conclusion

Structures and classes in Swift provide different behaviors and are suited for different use cases. Understanding the differences between them is essential for designing effective and efficient code. By leveraging the power of structures and classes, you can create flexible and reusable code that forms the foundation of your Swift applications.