Declaring class without defining

[Harish050887]

I have 3 classes in header file. The code looks somewhat like below. there is no problem for func_b() since class A is above it in the file. But I cant make the compiler to identify B from A for calling func_a(). How can I do it ? is there smthn like just declaration of the class without defining it as can be used for functions ?

 Class A{
void func_a(vector<B>&);
};

Class B{
void func_b(vector<A>&);
};

Class C{
vector<B> b;
vector<A> a;
}

[keskiverto]

Yes.
class B;

[Harish050887]

Thank you..!!! guess I should have tried that myself before posting here..!! its too simple..!! Thanks a lot...