Why is it mandatory for all classes implementing a protocol to have an initializer?

In Swift, if a protocol declares an initializer, all classes that implement this protocol are required to implement this initializer to ensure that any instance of the class can be created through this initializer. This is important for maintaining a consistent interface and the ability to use objects through the protocol without knowing the specific class.

For example, if a protocol requires an initializer with certain parameters, any class implementing the protocol must provide this initializer so that code working with the protocol can create objects generically.

protocol Initializable {
    init(value: Int)
}

class MyClass: Initializable {
    required init(value: Int) {
        // implementation
    }
}

The required keyword indicates that the initializer must be implemented in all subclasses, supporting the protocol's contract.