What are the differences between classes and structs?

Question

Accepted Answer

Classes and structs are both user-defined types in C++, differing mainly in default access levels and intended use cases.

Default access level: Classes default to private, while structs default to public.
Inheritance: Classes can be used for encapsulation and inheritance, whereas structs are typically used for plain data structures.
Use case: Classes are often used for complex data types with behavior, while structs are used for simple data aggregates.
Example: class MyClass { private: int x; }; struct MyStruct { int x; };

Accepted Answer

✅ Classes: Reference Types
Stored in the heap.
When you assign a class instance to another variable, both refer to the same object in memory.
Swift uses Automatic Reference Counting (ARC) to manage memory.
Every time a new reference to the object is made, the reference count increases.
When references are removed, the count decreases.
When the count reaches zero, the object is deallocated.
Example:
class Person {
    var name = "Alice"
}
var p1 = Person()
var p2 = p1
p2.name = "Bob"
print(p1.name) // Output: Bob (same reference)

✅ Structs: Value Types
Stored in the stack (unless captured by closures or stored in classes).
When you assign a struct to another variable, it is copied.
No reference counting is needed — each copy is independent.
Example:

struct Person {
    var name = "Alice"
}

var p1 = Person()
var p2 = p1
p2.name = "Bob"
print(p1.name) // Output: Alice (different copy)

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What are the differences between classes and structs?

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