callback vs lambda

Question

Suppose I have the following code that I wish to refactor:

int toFuture()
{
  precalc();
  int calc = 5 * foobar_x() + 3;
  postcalc();
  return calc;
}

int toP         


        

Answer 1

If you are wanting a template approach using C++11 features, that could look as simple as:

template
auto calculation(FuncType&& func) -> decltype(func())
{
    precalc();
    auto ret = func();
    postcalc();
    return ret;
}

You would then simply call your calculation function and pass it either a lambda, a functor, or a function-pointer. Your only souce of difficulty in this instance would be if you passed a function that had a void return-type ... in that case you will get a compiler error (which is a good thing vs. a runtime error).