Inheritance

[ankushnandan]

class A
{
	int n;
public:
	virtual void Fun1(int no=10)
	{
		n = no;
		cout<<"A::Fun1"<<n;
	}
};

class B : public A
{
	int m;
public:
	virtual void Fun1(int no=20)
	{
		m = no;		
		cout<<"B::Fun1()"<<m;
	}
};

int main()
{
	B b;
	A &a =b;
	a.Fun1();
}

When we execute it, B::Fun1() is being executed.

But it prints value of member variable of A class. Why??

[Bazzy]

Because it reads the default argument from A::Fun1, that information is not stored in the virtual table

[hamsterman]

http://www.cplusplus.com/forum/general/16189/#msg80512

[bluecoder]

Hi,
When you call the function only on the objec as line 2 .

 B b;
         b.Func1() ; 
	A &a =b;
	a.Fun1();

This is default value is complied at the complied time and you will get the value 20 .
Where in dynamic binding the default value of the of the derived class is lost and the value of the base class is taken

[ankushnandan]

Thanks All