/////////////////////////////////////////////////////////////////
//  invoker.cpp - defines class to wrap function pointers      //
//  Exam4:Q3                                                   //
//  Jim Fawcett, CSE687 - Object Oriented Design, Spring 05    //
/////////////////////////////////////////////////////////////////

#include <string>
#include <iostream>

template <typename R, typename A>
class delegate
{
public:
  typedef R(*fPtr)(A);

  virtual ~delegate() {}

  void operator+=(fPtr fp)
  {
    fptr_ = fp;
  }

  R operator()(A a)
  {
    return fptr_(a);
  }
private:
  fPtr fptr_;
};

int trunc(double d)
{
  return static_cast<int>(d);
}

struct Args
{
  int i;
  double d;
};

void simulateArgs(Args& a)
{
  std::cout << "\n  1st arg = " << a.i;
  std::cout << "\n  2nd arg = " << a.d;
}

void main()
{
  delegate<int,double> del;
  del += trunc;
  int r = del(3.5);
  std::cout << "\n  received " << del(3.5) << " from invoker\n\n";

  delegate<void,Args&> rdel;
  rdel += simulateArgs;
  Args a = { -3, 3.1415927 };
  rdel(a);

  std::cout << "\n\n";
}