/*
 * function-objects-01.cc    Standard Library, Funtion objects, exercise 1.
 */
#include <algorithm>
#include <functional>
#include <iostream>
#include <iterator>
#include <set>
using namespace std;

template<typename T> 
const T& median_of_three(const T& x, const T& y, const T& z)
{
   if ((y <= x && x <= z) || (z <= x && x <= y)) 
      return x;
   else if ((x <= y && y <= z) || (z <= y && y <= x)) 
      return y;
   else
      return z;
}


template<typename T> 
const T& median_of_three_set(const T& x, const T& y, const T& z)
{
   set<T> s{ x, y, z };
   return *(++s.begin());   
}

template<typename T> 
struct Median_Of_Three
{
   const T& operator()(const T& x, const T& y, const T& z) const 
   {
      if ((y <= x && x <= z) || (z <= x && x <= y)) 
	 return x;
      else if ((x <= y && y <= z) || (z <= y && y <= x)) 
	 return y;
      else
	 return z;
   }
};

int main()
{
   cout << "Function:\n";
   cout << median_of_three(1, 2, 3) << '\n';
   cout << median_of_three(1, 3, 2) << '\n';
   cout << median_of_three(2, 1, 3) << '\n';
   cout << median_of_three(2, 3, 1) << '\n';
   cout << median_of_three(3, 1, 2) << '\n';
   cout << median_of_three(3, 2, 1) << '\n';

   cout << "Function using set:\n";
   cout << median_of_three_set(1, 2, 3) << '\n';
   cout << median_of_three_set(1, 3, 2) << '\n';
   cout << median_of_three_set(2, 1, 3) << '\n';
   cout << median_of_three_set(2, 3, 1) << '\n';
   cout << median_of_three_set(3, 1, 2) << '\n';
   cout << median_of_three_set(3, 2, 1) << '\n';

   cout << "Function object:\n";
   cout << Median_Of_Three<int>()(1, 2, 3) << '\n';
   cout << Median_Of_Three<int>()(1, 3, 2) << '\n';
   cout << Median_Of_Three<int>()(2, 1, 3) << '\n';
   cout << Median_Of_Three<int>()(2, 3, 1) << '\n';
   cout << Median_Of_Three<int>()(3, 1, 2) << '\n';
   cout << Median_Of_Three<int>()(3, 2, 1) << '\n';

   return 0;
}