26. What is a delegate?
A delegate is same as to a class which is used for storing the reference to a method and invocating that method at runtime , as required. A delegate can hold the reference of only those methods whose signatures are same as that of the delegate. Some of the examples of delegates are type-safe functions, pointers, or callbacks.
27. What is the syntax to inherit from a class in C#?
When a class is derived from another class, then the members of the base class become the members of the derived class. The access modifier used while accessing members of the base class secludes the access status of the base class members inside the derived class.
The syntax to inherit a class from another class in C# is as follows: class MyNewClass : MyBaseclass
28. State the features of an interface.
An interface is a generic model that contains only the signature of methods. The signature of a method consists of the numbers of parameters, the type of parameter (value, reference, or output), and the order of parameters. An interface has no accomplishment on its own because it contains only the definition of methods without any method body. An interface is defined using the interface keyword. Moreover, you cannot instantiate an interface. The various features of an interface are as follows:
• An interface is used to appliance multiple inheritance in code. This feature of an interface is quite different from that of abstract classes because a class cannot obtain the features of more than one class but can easily implement multiple interfaces.
• It defines a specific set of methods and their arguments.
• Variables in interface must be declared as public, static, and final while methods must be public and abstract.
• A class implementing an interface must implement all of its methods. • An interface can derive from more than one interface.
29. Can you use the 'throws' clause to raise an exception?
No, the throws clause cannot be used to raise an exception. The throw statement signals the instance of an exception during the execution of a program. When the program encounters a throw statement, the method terminates and returns the error to the calling method.
30. Define an array.
An array is considered as a homogeneous collection of elements, stored at contiguous memory locations, which can be referred by the same variable name. All the elements of an array variable can be accessed by index values. An Index value specifies the position of a particular element in an array variable.