What are value types in Swift?

What are value types?

Value types play a central role in programming languages by grouping data values.

`Value type” is a type of data copied when assigned to a new variable.

struct Storage {
    var data: String = "some data"
}
let originalStorage = Storage()
var copiedStorage = originalStorage  // `originalStorage` is copied to `copiedStorage`

How can you pass value types?

You can pass value type by copying value.

struct Storage {
    var data: String = "some data"
}
let originalStorage = Storage()
var copiedStorage = originalStorage                        // `originalStorage` is copied to `copiedStorage`
copiedStorage.data = "new data"                            // Changes `copiedStorage`, not `originalStorage`
print("\(originalStorage.data), \(copiedStorage.data)")    // prints "some data, new data"

The effect of assignment, initialization, and argument passing creates an independent instance with a unique copy of its data.

What types are value types?

Value types can be struct, enum, tuple.

What data types are value types?

Strings, Arrays, Dictionaries, Numbers, Booleans, Floating-point numbers, and Integers are all value types.

How value types are stored in memory?

The value types use Stack data structure for memory management.

What is Copy-on-write mechanism?

The copy-on-write mechanism is a resource-management technique used to optimize value types performance. It improves performance by avoiding unnecessary copies of value types. If resource is duplicated but not modified it’s unnecessary to create new resource.

When to use value types?

Choose value types if you don’t have shared mutable state.