How to use function pointer between 2 classes - c++

Question

i have 2 classes say "Class A" and "Class B". i tried to declare the function pointer prototype in "Class A" and use it in "Class B", but failed. Please look in to my sample code and assist me how to make it success.
#include "stdafx.h"
#include <iostream>
using namespace std;
class A
{
public:
int (*funcPtr)(int,int);
void PointerTesting(int (*funcPtr)(int,int))
{
//i need to get B::test as an function pointer argument
}
};
class B
{
public:
int test(int a,int b)
{
return a+b;
}
};
int _tmain(int argc, _TCHAR* argv[])
{
int (A::*fptr) (char*) = &B::test;
getchar();
return 0;
}

Answer 1

Recommendation: Use < functional >, std::function and std::bind
#include <iostream>
#include <functional>
using namespace std;
class A {
public:
using FnPtr = std::function<int(int, int)>;
void PointerTesting(const FnPtr& fn) {
//i need to get B::test as an function pointer argument
// Example: Print 1 and 2's sum.
int result = fn(1, 2);
std::cout << "Result: " << result << std::endl;
}
};
class B {
public:
int test(int a,int b) {
return (a+b);
}
};
int main(int argc, char* argv[]) {
A a;
B b;
A::FnPtr ptr = std::bind(&B::test, b, std::placeholders::_1, std::placeholders::_2);
a.PointerTesting(ptr);
getchar();
return 0;
}
http://en.cppreference.com/w/cpp/utility/functional/bind
http://en.cppreference.com/w/cpp/utility/functional/function