Can I create anonymous classes in C++ and capture the outside variables like in Java?

Question

In Java, when I need a callback function, I have to implement an anonymous class. Inside the anonymous class, I can access the outside variables if they\'re final

Answer 1

If your IA class really has just one virtual method that you need to override (and the real complexity is other non-virtual methods) but you don't want to capture the local variables that this method needs, how about this:

int main() {
  int y = 100;
  auto f = [=](int x){return x+y;};
  typedef decltype(f) F;
  struct IB : IA {
    F _f;
    IB(F _f): _f(_f) {}
    int f(int x) { return _f(x); }
  } a(f);
  doFancyWork(&a);
  return 0;
}