the C++ have virtual functions, but, for me they have 1 problem: on derived class, i must prototype them, for define them on Global Scope.
how can i avoid the re-prototype them on derived class?
i tried 1 way:
template <class Type>
class TypeHasToString
{
// This type won't compile if the second template parameter isn't of type T,
// so I can put a function pointer type in the first parameter and the function
// itself in the second thus checking that the function has a specific signature.
template <typename T, T> struct TypeCheck;
typedef char Yes;
typedef long No;
// A helper struct to hold the declaration of the function pointer.
// Change it if the function signature changes.
template <typename T> struct ToString
{
typedef void (T::*fptr)();
};
template <typename T> static Yes HasToString(TypeCheck< typename ToString<T>::fptr, &T::MouseClick >*); //function name
template <typename T> static No HasToString(...);
public:
static bool const value = (sizeof(HasToString<Type>(0)) == sizeof(Yes));
};
template <typename CBase>
class test
{
CBase* atPointer = nullptr;
public:
void MouseClick(){;};
test(CBase *clsPointer) : atPointer(clsPointer)
{
atPointer=clsPointer;
//use it:
std::cout << TypeHasToString<CBase>::value;
}
void call()
{
atPointer->MouseClick();
}
};
//ClassWithEvents(test,FormEvents, b);
class InstanceName : public test<InstanceName>
{ // manual expansion of ClassWithEvents
public:
InstanceName() : test(this){;}
~InstanceName(){;}
public:
void MouseClick();
// void Move(); // error 1
} InstanceName;
// void b::MouseClick() // possible error 2
void InstanceName::MouseClick()
{
std::cout << "Mouse click";
}these template is for test if the class test::CBase have the MouseClick().
these code works, but it's limited: if we have the function prototype(but not defined), i will get '1' instead zero.
so what you can advice me more?