I have two classes A and B. I want to pass a function name in class A as parameter of function in Class B. I tried with below sample, Is it correct way.
class A
{
public:
B m_b;
void MyFun()
{
// do something
}
void Test()
{
m_b.Process( MyFun );
}
}
class B
{
public:
void Process( void (*f)() )
{
(*f)();
}
}
thanks in advance
Since MyFun is a member function of class A, you need a pointer-to-member instead of a regular function pointer, and you also need an instance of class A to invoke the function on:
class B
{
public:
void Process(A *obj, void (A::*f)() )
{
(obj->*f)();
}
}
Actually, if MyFun is not a static member of your class, it has a hidden argument that is of type A*, so this is implemented like: m_a.MyFun(...) =~ MyFunImpl(&m_a, ...).
So, What you want is probably have a static function MyFun (you can't use this inside it), and inside B::Process call f().
If you need to pass this, refer to casablanca's answer (pointers to member functions).
Otherwise, if you want to pass an argument, you can lookup std::bind or lambda functions (C++0x), or boost::bind prior to that.
Follow the advice here: http://www.parashift.com/c++-faq-lite/pointers-to-members.html#faq-33.4, you'll end up with this:
class A;
typedef void (A::*MemFun)();
class B
{
public:
void Process(A& a, MemFun mf)
{
(a.*mf)();
}
};
class A
{
public:
B m_b;
void MyFun()
{
// do something
}
void Test()
{
MemFun p = &A::MyFun;
A a;
m_b.Process(a, p);
}
};
