How is the default object reference determined in a programming language?

In programming languages, a default reference to an object is defined as a pointer or reference that points to a specific instance of an object in memory. Depending on the language, this can be:

• In Swift and Objective-C — a reference to a class object that stores the address of the object in the heap.
• In managed memory languages — a reference that is automatically managed by a garbage collector.

For example, in Swift:

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

let person = Person(name: "Alex")
// 'person' is a reference to a Person object in memory

Here, person is a reference to a Person object. By default, when you assign an object to a variable, you are working with a reference, not a copy of the object.

Thus, a default reference is a way to access an object in memory, allowing you to work with the same instance from different parts of the program.