Access Levels in Swift

// Access control levels
open class OpenClass {  // Subclassable outside module
    open func openMethod() { }  // Overridable outside module
}

public class PublicClass {  // Accessible outside module
    public func publicMethod() { }  // Not overridable outside
}

internal class InternalClass {  // Default - module only
    func internalMethod() { }  // Default is internal
}

fileprivate class FilePrivateClass {  // Current file only
    fileprivate func filePrivateMethod() { }
}

private class PrivateClass {  // Current scope only
    private func privateMethod() { }
}

// Property access control
public struct PublicStruct {
    public private(set) var readOnlyOutside: Int = 0
    internal var internalProperty: String = ""
    fileprivate var filePrivateProperty: Bool = false
    private var privateProperty: Double = 0.0
}