Tutorial on poLymorphism ,Exception Handling Types
What you will learn
types of polymorphism
the exception types
exception and errors
Polymorphism in C#
Polymorphism is a Greek word, meaning “one name many forms”. In other words, one object has many forms or has one name with multiple functionalities. “Poly” means many and “morph” means forms. Polymorphism provides the ability to a class to have multiple implementations with the same name. It is one of the core principles of Object Oriented Programming after encapsulation and inheritance. In this article, you’ll learn what polymorphism is, how it works, and how to implement polymorphism in C#.
Types of Polymorphism
There are two types of polymorphism in C#:
- Static / Compile Time Polymorphism.
- Dynamic / Runtime Polymorphism.
Static or Compile Time Polymorphism
It is also known as Early Binding. Method overloading is an example of Static Polymorphism. In overloading, the method / function has a same name but different signatures. It is also known as Compile Time Polymorphism because the decision of which method is to be called is made at compile time. Overloading is the concept in which method names are the same with a different set of parameters.
Here C# compiler checks the number of parameters passed and the type of parameter and make the decision of which method to call and it throw an error if no matching method is found.
- Dynamic / runtime polymorphism is also known as late binding. Here, the method name and the method signature (number of parameters and parameter type must be the same and may have a different implementation). Method overriding is an example of dynamic polymorphism.
Method overriding can be done using inheritance. With method overriding it is possible for the base class and derived class to have the same method name and same something. The compiler would not be aware of the method available for overriding the functionality, so the compiler does not throw an error at compile time. The compiler will decide which method to call at runtime and if no method is found then it throws an error.
An exception is a problem that arises during the execution of a program. A C# exception is a response to an exceptional circumstance that arises while a program is running, such as an attempt to divide by zero.
Exceptions provide a way to transfer control from one part of a program to another. C# exception handling is built upon four keywords: try, catch, finally, and throw.
- try − A try block identifies a block of code for which particular exceptions is activated. It is followed by one or more catch blocks.
- catch − A program catches an exception with an exception handler at the place in a program where you want to handle the problem. The catch keyword indicates the catching of an exception.
- finally − The finally block is used to execute a given set of statements, whether an exception is thrown or not thrown. For example, if you open a file, it must be closed whether an exception is raised or not.
- throw − A program throws an exception when a problem shows up. This is done using a throw keyword.