19. Define enumeration?
Enumeration is defined as a value type that consists of a set of named values. These values are constants and are called enumerators. An enumeration type is declared using the enum keyword. Each enumerator in an enumeration is associated with an underlying type that is set, by default, on the enumerator. The following is an example that creates an enumeration to store different varieties of fruits:
enum Fruits {Mango, Apple, orange, Guava};
In the preceding example, an enumeration Fruits is created, where number 0 is associated with Mango, number 1 with Apple, number 2 with Orange, and number 3 with Guava. You can access the enumerators of an enumeration by these values.
20. In which namespace, all .NET collection classes are contained?
The System.Collections namespace contains all the collection classes.
21. Is it a good practice to handle exceptions in code?
Yes, you must handle exceptions in code so that you can deal with any unexpected situations that occur when a program is running. For example, dividing a number by zero or passing a string value to a variable that holds an integer value would result in an exception.
22. Explain the concept of constructor?
Constructor is a special method of a class, which is called automatically when the instance of a class is created. It is created with the same name as the class and initializes all class members, whenever you access the class. The main features of a constructor are as follows:
Constructors do not have any return type
Constructors are always public
It is not mandatory to declare a constructor; it is invoked automatically by .NET Framework.
23. Can you inherit private members of a class?
No, you cannot inherit private members of a class because private members are accessible only to that class and not outside that class.
24. Does .NET support multiple inheritance?
.NET does not support multiple inheritance directly because in .NET, a class cannot inherit from more than one class. .NET supports multiple inheritance through interfaces.
