Dynamic function call C++ - c++

Question

I would like to do something like this:
class Base{};
class Specialized1 : public Base
{
public:
int GetCount(){ return 1; }
};
class Specialized2 : public Base
{
public:
bool IsCorrect() { return true; }
};
class Example
{
public:
template< class ATTR_CLASS, class RETURNED_PARAMETER_CLASS >
int GetPerfectAttributeIndex( const RETURNED_PARAMETER_CLASS & perfect_parameter, ***RETURNED_PARAMETER_CLASS (*function_to_call)()*** )
{
for ( int i = 0; i < AttributeCount; ++i )
{
if ( perfect_parameter ==
static_cast< ATTR_CLASS >( MyAttributeTable[ i ] )->function_to_call() )
{
return i;
}
}
return -1;
}
Base** MyAttributeTable;
int AttributeCount;
};
And the call would be:
example.GetPerfectAttributeIndex< Specialized1, int >( 1, &Specialized1::GetCount );
So I know that this code is not working because of the part between ***
But how can I change it to make it work? Using some C++11 magic?
Thank you for any help!

Answer 1

The problem is that function_to_call is not a pointer to member function. You should also downcast from Base* more safe with dynamic_cast and checking against nullptr afterwards.
class Base
{
public:
virtual ~Base() = default;
};
class Specialized1 : public Base
{
public:
int GetCount() { return 1; }
};
class Specialized2 : public Base
{
public:
bool IsCorrect() { return true; }
};
class Example
{
public:
template <class ATTR_CLASS, class RETURNED_PARAMETER_CLASS>
int GetPerfectAttributeIndex(
RETURNED_PARAMETER_CLASS const& perfect_parameter,
RETURNED_PARAMETER_CLASS(ATTR_CLASS::*function_to_call)()) // added ATTR_CLASS::
{
for(int i = 0; i < AttributeCount; ++i)
{
auto ptr = dynamic_cast<ATTR_CLASS*>(MyAttributeTable[i]);
if(!ptr)
{
// handle the case of an invalid cast
}
if(perfect_parameter == (ptr->*function_to_call)()) // extra parentheses added and ->* operator used
return i;
}
return -1;
}
Base** MyAttributeTable;
int AttributeCount;
};