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#include <iostream>
 
namespace exercise {
 
class A {
public:
 
    virtual void a() = 0;
    virtual void b() = 0;
    virtual void c() = 0;
 
};
 
class B : public A {
 
    void a() { std::cout << "a function @ B class"; }
    void b() { std::cout << "b function @ B class"; }
    void c() { std::cout << "c function @ B class"; }
 
};
 
class C : public A {
 
    void a() { std::cout << "a function @ C class"; }
    void b() { std::cout << "b function @ C class"; }
    void c() { std::cout << "c function @ C class"; }
};
 
using Pstd_mem = void(A::*)();
 
void foo(A* basePointer, Pstd_mem action) {
 
    basePointer->*action();
 
}
}
 
int main(void) {
 
using namespace exercise;
 
A* b = new B();
A* c = new C();
 
foo(b, &A::b);
 
}

prog.cpp: In function ‘void exercise::foo(exercise::A*, exercise::Pstd_mem)’:
prog.cpp:33:26: error: must use ‘.*’ or ‘->*’ to call pointer-to-member function in ‘action (...)’, e.g. ‘(... ->* action) (...)’
     basePointer->*action();
                          ^
prog.cpp: In function ‘int main()’:
prog.cpp:43:4: warning: unused variable ‘c’ [-Wunused-variable]
 A* c = new C();
    ^

Standard output is empty