#include <iostream>
#include <cstdlib>  // for random number generator
#include <ctime>
#include <fstream> // for writing to the file
using namespace std;

class SquareMatrix {
 public:
   class Row;
   friend class Row;

   SquareMatrix(unsigned int side)
        : side_(side), values_(new int[side*side])
   {
   }
   ~SquareMatrix() { delete [] values_; }
   SquareMatrix(const SquareMatrix &) = delete;
   SquareMatrix(SquareMatrix &&other)
        : side_(other.side_), values_(other.values_)
   {
      other.values_ = nullptr;
   }

   const SquareMatrix &operator =(const SquareMatrix &) = delete;
   const SquareMatrix &operator =(SquareMatrix &&) = delete;

   unsigned int size() const { return side_ ; }

   inline Row operator [](unsigned int row);
   inline const Row operator [](unsigned int row) const;

 private:
   const unsigned int side_;
   int *values_;
};

class SquareMatrix::Row {
   friend class SquareMatrix;

 public:
   const Row &operator =(const Row &) = delete;
   const Row &operator =(Row &&) = delete;

   int &operator [](unsigned int col) {
      return matrix_.values_[row_ * matrix_.side_ + col];
   }
   int operator [](unsigned int col) const {
      return matrix_.values_[row_ * matrix_.side_ + col];
   }

 private:
   SquareMatrix &matrix_;
   const unsigned int row_;

   Row(Row &&) = default;
   Row(SquareMatrix &m, unsigned int row)
        : matrix_(m), row_(row)
   {
   }
};

inline SquareMatrix::Row SquareMatrix::operator [](unsigned int row)
{
   return Row(*this, row);
}

inline const SquareMatrix::Row SquareMatrix::operator [](unsigned int row) const
{
   return Row(*const_cast<SquareMatrix *>(this), row);
}

int main()
{

   int array_sizes[6] = {32,64,128,256,512,1024};

   int m;
   ofstream results; //output the results
   results.open ("results.txt");

   for(int i = 0; i < 6; i++){
      for (int k = 0; k < 3; k ++){

         clock_t start = clock();
         m = array_sizes[i];

         {
            SquareMatrix A(m), B(m), product(m);

            // Initialize A[I][K]
            // I x K == row * inner
            for(int row = 0; row < m; row++) {
               for(int inner = 0; inner < m; inner++){
                  A[row][inner] = 5;
               }
            }


            for(int row = 0; row < m; row++) {
               for(int inner = 0; inner < m; inner++){
                  B[row][inner] = 3;
                  //cout << B[row][inner] << " ";
               }
               //cout << "\n";
            }

            // main routine for multiplication
            for(int row = 0; row < m; row++) {
               for(int col = 0; col < m; col++) {
                  product[row][col] = 0;
                  for(int inner = 0; inner < m; inner++) {
                     product[row][col] += A[row][inner] * B[inner][col];
                  }
                  //cout << product[row][col] << " ";
               }
               //cout << "\n";
            }
         }

         clock_t end = clock();
         double cpu_time = static_cast<double>(end - start)/CLOCKS_PER_SEC;

         results << cpu_time << endl;
      }
      results << m << endl;
   }

   results.close();
   return 0;
}