Get set in Swift

In Swift, we can use the get and set keywords to define computed properties in a class. Computed properties are properties whose value is not stored, but rather computed each time it is accessed.

Let's say we have a class called Person that has a property called age. We can define this property as a computed property using get and set as follows:

class Person {
   var _age: Int = 0 // underscore is used to indicate it is not meant to be accessed outside of the class
   
   var age: Int {
      get {
         return _age
      }
      set(newValue) {
         _age = newValue
      }
   }
}

When we create an instance of the Person class, we can set the value of the age property using the set method:

let person = Person()
person.age = 25 // This will call the set method

We can also get the value of the age property using the get method:

print(person.age) // This will call the get method and print 25

In the above example, we are using a private variable _age to store the actual value of the age property. When we set person.age to a new value, the set method is called and it sets the value of _age. Similarly, when we try to access the value of person.age, the get method is called, which returns the value of _age.

Note that in the above example, we don't have to explicitly call the get and set methods - Swift automatically calls them when we access or set the age property.