In which cases is it preferable to use reference types in programming?

Reference types are preferable when working with large or complex objects to avoid copying data and improve performance. Instead of creating a copy of an object, the variable holds a reference to the same object in memory.

This is convenient when:

• Multiple parts of a program need access to the same object state.
• Objects are large, and copying is resource-intensive.
• The object needs to be modified from different parts of the code.

For example, in iOS (Swift), classes are reference types, while structures are value types. If changes to an object should be visible in different places, a class is used:

class User {
    var name: String
    init(name: String) {
        self.name = name
    }
}

let user1 = User(name: "Alice")
let user2 = user1
user2.name = "Bob"
print(user1.name) // Outputs "Bob" because user1 and user2 refer to the same object

If User were a structure (a value type), changes to user2 would not affect user1.