/////////////////////////////////////////////////
// MT1Q5.cpp - Bounds Checking template Policy //
//                                             //
// Jim Fawcett, CSE687 - Midterm, Spring 2010  //
/////////////////////////////////////////////////

#include <exception>
#include <iostream>

class NoBoundsCheck
{
public:
  template <size_t N>
  static void range_of(size_t i) {}
};

class BoundsCheck
{
public:
  template <size_t N>
  static void range_of(size_t i)
  {
    if(i<0 || N<= i)
      throw std::exception("range error");
  }
};

template<typename T, size_t N, typename Check>
class Array
{
public:
  Array();
  Array(const Array& a);
  ~Array();
  Array& operator=(const Array& a);
  T& operator[](size_t n);
  T operator[](size_t n) const;
private:
  T* array_;
};

template<typename T, size_t N, typename Check>
Array<T,N,Check>::Array() : array_(new T[N]) {}

template<typename T, size_t N, typename Check>
Array<T,N,Check>::Array(const Array& a) : array_(new T[N])
{
  for(size_t i=0; i<N; ++i)
    array_[i] = a.array_[i];
}

template<typename T, size_t N, typename Check>
Array<T,N,Check>::~Array()
{
  delete [] array_;
}

template<typename T, size_t N, typename Check>
Array<T,N,Check>& Array<T,N,Check>::operator=(const Array<T,N,Check>& a)
{
  if(this == &a) return *this;
  delete [] array_;
  array_ = new T[N];
  for(size_t i=0; i<N; ++i)
    array_[i] = a.array_[i];
}

template<typename T, size_t N, typename Check>
T& Array<T,N,Check>::operator [](size_t n)
{
  Check::range_of<N>(n);
  return array_[n];
}

template<typename T, size_t N, typename Check>
T Array<T,N,Check>::operator [](size_t n) const
{
  Check::range_of<N>(n);
  return array_[n];
}

void main()
{
  std::cout << "\n  MT1Q5 - Bounds Checking Template Policy";
  std::cout << "\n =========================================\n";

  try
  {
    // if you replace BoundsCheck with NoBoundsCheck
    // a heap corruption Assert is thrown

    Array<double,4,BoundsCheck> arr;
    for(size_t i=0; i<4; ++i)
      arr[i] = i + 0.5;

    std::cout << "\n  ";
    for(size_t i=0; i<4; ++i)
      std::cout << arr[i] << " ";

    arr[-1] = arr[5];
    std::cout << "\n\n";
  }
  catch(std::exception& ex)
  {
    std::cout << "\n\n  " << ex.what() << "\n\n";
  }
}