/////////////////////////////////////////////////////////////////
// foreach.cpp - demonstrates use of foreach algorithms        //
//                                                             //
// Jim Fawcett, CSE687 - Object Oriented Design, Spring 2005   //
/////////////////////////////////////////////////////////////////

#include <algorithm>
#include <list>
#include <vector>
#include <iostream>

template <typename T>
struct showEach
{
  void operator()(const T& t) const { std::cout << t << " "; }
};

template <typename C>
void show(const C& c)
{
  std::cout << "\n  ";
  for_each(c.begin(), c.end(), showEach<C::value_type>());
  std::cout << "\n";
}

template <typename T>
class Sum 
{
public:
  Sum() : sum_(0) {}
  void operator()(T& t) { sum_ += t; }
  T result() { return sum_; }
private: 
  T sum_;
};

void main()
{
  std::cout << "\n  Demonstrating for_each Algorithm "
            << "\n ==================================\n";

  int array[13] = { -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
  std::list<int> li(&array[0], &array[13]);
  show(li);
  
  // foreach is the only algorithm that returns its operation, e.g., Sum()

  int sum = for_each(li.begin(),li.end(),Sum<int>()).result();
  std::cout << "\n  sum of list = " << sum << "\n\n";

  double darray[10] = { -2.5, -1.5, 0, 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, 7.5 };
  std::vector<double> vd(&darray[0], &darray[10]);
  show(vd);

  double dsum = for_each(vd.begin(),vd.end(),Sum<double>()).result();
  std::cout << "\n  sum of list = " << dsum << "\n\n";
}