Multiple Inheritance

Question

Instead of multiple inheritance we are using Interface. Why multiple inheritance does not support in C# Language?

Manas Mohapatra · Answer

Hi Vignesh, C# doesn't support multiple inheritance due to following reason: Diamond problem: Suppose there is a class called Word and contains method called Print(). There is a another class called PDF and also contain method called Print(). Now class GenericDoc inherits from above two classes(Word, PDF). Problem is when you will try to call Print() because how compiler will know which class method will call - so it creates ambiguity . Hope you understand the problem. Note: If you find anything useful in my answer please accept my answer.

Upendra Pratap Shahi · Answer

C# not support multiple inheritance due to diamond problem. What is wrong with multiple inheritance? The main problem with multiple inheritance is that there can be times when the results of using multiple inheritance will be uncertain. The best example of this is the classic problem known as the diamond problem where a class inherits from 2 different classes, but those 2 different classes inherit from the same class, like in the graphic below (where class D derives from both classes B and C, and classes B and C both derive from class A: And here is what the code for that example would look like: class A { protected: bool testing; }; class B: public A { }; class C: public A { }; class D: public B, public C { public: void setTesting ( bool xTesting) { testing = xTesting; // this is uncertain } }; In the code above we have the testing data member which is defined by class A. But, the problem is that class D derives from both classes B and C, which both derive from class A. This means that there are essentially 2 copies of the testing flag that are available because there are 2 instances of A in D’s class hierarchy. So, this creates a problem because which copy of the testing flag will be set? And the compiler will give an error and say that the reference to testing in class D is ambiguous. But, there are some fixes to this problem. One fix is to make it very clear which classe’s version of testing is going to be set: B :: testing = xTesting; // use B's version of testing The other fix for this problem is to declare B and C as virtual base classes. This allows only one copy of A to be created for class D, and that clears up any ambiguities. Read more here to understand that in more depth.

Pankaj Kumar Choudhary · Answer

Hello @Vignesh Multiple inheritance allows people to create classes that combine aspects of different classes and their corresponding hierarchies. This is something that is quite common because applications often need to use the frameworks of different classes to achieve the desired functionality. Suppose that you are trying to create a class that models the animal known as a Liger, which is the result of having a Tiger and a Lion mate. Then you would create a class called Liger that derives from both the Tiger and Lion classes – so the Liger class would have to use multiple inheritance since it is deriving or inheriting from 2 different classes. http://www.programmerinterview.com/index.php/general-miscellaneous/why-dont-c-and-java-support-multiple-inheritance/

Rajeesh Menoth · Answer

Hi Vignesh Mani , Some ref : http://www.c-sharpcorner.com/UploadFile/cbreakspear/MultipleInheritance11082005004843AM/MultipleInheritance.aspx

Multiple Inheritance

Answers (4)