Chapter 17 Classes

1protected C(): base() {}

2or

3public C(): base() {}

4where C is the name of the class. end note]

5[Example: In the following code

6class Message

7{

9string text;

10}

11a default constructor is provided because the class contains no instance constructor declarations. Thus, the

12example is precisely equivalent to

13class Message

14{

17public Message(): base() {}

18}

19end example]

2017.10.5 Private constructors

21When a class declares only private instance constructors, it is not possible for other classes (that are not

22nested in the class) to derive from that class or to create instances of that class. [Example: Private instance

23constructors can be used to restrict instantiation of the class to a prescribed set of instances. For example:

24public class Color

25{

42}

43}

44Since Color’s constructor is private, there will never be more than three instances of the Color class,

45namely the ones stored in the static fields and returned by the static properties. end example]

46At least one instance constructor shall be declared to suppress the automatic generation of a default

47constructor.

4817.10.6 Optional instance constructor parameters

49[Note: The this(…) form of constructor initializer is commonly used in conjunction with overloading to

50implement optional instance constructor parameters. In the example

315