calling a member function of different class from another class

Question

I have two classes A and B. The control is inside one of the member functions of class A. The member function calculates a result and i now want to send this value to one of the member functions of class B, I tried the following way, yet it dint work

 int memberFunctionOfA() { ... //results are stored in some temporary value, say temp B::memberFunctionOfB(temp); // the way i tried }

The comiler reported an error. I also tried like

 B obj; obj.memberFunctionOfB(temp);

Both gave me errors that the memberFunctionOfB cannot be called. Can anyone tell me what am i missing

Edit

Class B is not inherited from A. They both are independent. Both the member functions are public and non static

@CHID I don't understand memberFunctionOfB is static function? — UmmaGumma
– UmmaGumma, Commented Feb 13, 2011 at 20:18
The declaration of class B would help a lot here. If A inherits from B (or the other way around), class A's declaration would help as well. First guess, i'd say memberFunctionOfB is private/protected, but it's hard to say for sure without seeing the code. — cHao
– cHao, Commented Feb 13, 2011 at 20:20
@CHID: That particular error means your class B doesn't have a default constructor. IF you want to create a B, you'll need to supply arguments -- like B obj(42, "These are sample args"); rather than just B obj;. Look through the code for class B and find out what its constructor expects. — cHao
– cHao, Commented Feb 13, 2011 at 20:23
compiler said your class B doesn't have default constructor which is required to create object on the stack like you do here: B obj; — Andriy Tylychko
– Andriy Tylychko, Commented Feb 13, 2011 at 20:23

Michael Goldshteyn · Accepted Answer · 2011-02-13 20:17:38Z

Your second attempt:

int memberFunctionOfA() { ... //results are stored in some temporary value, say temp B obj; obj.memberFunctionOfB(temp); }

..., looks perfectly valid. We will need the definition of B to help further. B's definition should minimally have, assuming that the member function in B is non-static:

class B { public: void memberFunctionOfB(const TypeOfTemp &temp); }; // Later in class A's definition class A { public: int memberFunctionOfA() { ... //results are stored in some temporary value, say temp B b; b.memberFunctionOfB(temp); } };

If the member function in B is static, then this should work:

class B { public: static void memberFunctionOfB(const TypeOfTemp &temp); }; ... class A { public: int memberFunctionOfA() { ... //results are stored in some temporary value, say temp B::memberFunctionOfB(temp); } };

BenMorel · Accepted Answer · 2014-01-06 11:24:57Z

After seeing your comment:

The compiler throws "No matching function call B::B()"

That means, there is no default constructor for class B. In your implementation, B`s constructor must be taking parameter.

So either you add a default constructor to your class, or you pass the argument to your constructor when creating an instance of it.

Thank you nawaz. As they pointed out, i missed the default constructor.

Collectives™ on Stack Overflow

calling a member function of different class from another class

2 Answers 2

Comments

1 Comment

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Linked

Related