Syntax differences between C # and Java polymorphism

Syntax differences between C # and Java polymorphism

2016-11-29

Java code:

 Public Static voidMain (string[] args) {Mother Mother=Newmother ();        Mother.showname (); Mother Human=NewSon ();        Human.showname (); Son Sona=NewSon ();    Sona.showname ();}  Public classMother { Public voidShowName () {System.out.println (Mom); }} Public classSonextendsMother { Public voidShowName () {System.out.println (Son); }    }

Results:

Mom Son son

C # code:

    classProgram { Public Static voidMain () {Mother Mother=Newmother (); Mother.            ShowName (); Mother Human=NewSon (); Human.            ShowName (); Son Sona=NewSon (); Sona.            ShowName ();        Console.read (); }    }     Public classMother { Public Virtual voidShowName () {Console.WriteLine ("mom"); }    }     Public classSon:mother { Public Override voidShowName () {Console.WriteLine ("son"); }    }

Results:

Mom Son son

but if the override is gone, a line of warnings will appear, but the compiler will not error:

Warning 1 "ConsoleApplication1.Son.ShowName ()" Hides the inherited member "ConsoleApplication1.Mother.ShowName ()". If it is intentionally hidden, use the keyword new

The result is:

Mom Mom Son

Conclusion:

This proves that C # does not support polymorphism by default, and subclasses have a new keyword by default. C # to implement more than one need to add virtual and override before a method

In addition, polymorphism refers to the method, see only Polymorphic method, no polymorphic instance field

Syntax differences between C # and Java polymorphism