#include <iostream>
#include <stdlib.h>

using namespace std;


class MyMatrix
{
  public:
    MyMatrix(int dimension);
    MyMatrix(int rows, int columns);
    ~MyMatrix();

    void print();
    int get_rows();
    int get_columns();

    double get_element(int row, int column);
    void set_element(int row, int column, double value);

    MyMatrix operator + (MyMatrix A);
    MyMatrix operator * (MyMatrix A);
    void operator = (MyMatrix A);


  private:
    double* m;
    int row_d;
    int col_d;
    int d;
};

MyMatrix::MyMatrix(int dimension)
{
  row_d = dimension;
  col_d = dimension;
  d = dimension*dimension;
  m = new double[d];

  unsigned int k=0;
  for(unsigned int i=0; i<row_d; i++) {
    for(unsigned int j=0; j<col_d; j++) {
      if(i==j) {
          m[k] = 1;
      } else {
        m[k] = 0;
      }
      k++;
    }
  }
}

MyMatrix::MyMatrix(int rows, int columns)
{
  row_d = rows;
  col_d = columns;
  d = rows*columns;
  m = new double[d];


  srand(time(NULL));
  for(unsigned int i=0; i<d; i++) {
    m[i] = 1+(rand()%(100-1+1));
  }
}

MyMatrix::~MyMatrix()
{
  delete[] m;
}

void MyMatrix::print()
{
  unsigned int k=0;
  for(unsigned int i=0; i<row_d; i++) {
    for(unsigned int j=0; j<col_d; j++) {
      cout << m[k] << " ";
      k++;
    }
    cout << endl;
  }
}

int MyMatrix::get_rows()
{
  return row_d;
}

int MyMatrix::get_columns()
{
  return col_d;
}


double MyMatrix::get_element(int row, int column)
{
  // first element is 1,1!
  if((row*column)<=0) {
    return -1;
  }
  return m[((row-1)*col_d)+(column-1)];
}

void
MyMatrix::set_element(int row, int column, double value)
{
  if((row*column)>0) {
    m[((row-1)*col_d)+(column-1)] = value;
  }
}


MyMatrix
MyMatrix::operator + (MyMatrix A)
{
  MyMatrix* res = new MyMatrix(row_d, col_d);

  unsigned int k=0;
  for(unsigned int i=0; i<row_d; i++) {
    for(unsigned int j=0; j<col_d; j++) {
      res->m[k] = m[k]+A.get_element(i+1, j+1);
      k++;
    }
  }

  return *res;
}

MyMatrix MyMatrix::operator * (MyMatrix A)
{
  MyMatrix* res = new MyMatrix(row_d, col_d);

  unsigned int k=0;
  for(unsigned int i=0; i<row_d; i++) {
    for(unsigned int j=0; j<col_d; j++) {
      res->m[k] = m[k]*A.get_element(i+1, j+1);
      k++;
    }
  }

  return *res;
}

void MyMatrix::operator = (MyMatrix A)
{
  unsigned int k=0;
  for(unsigned int i=0; i<A.get_rows(); i++) {
    for(unsigned int j=0; j<A.get_columns(); j++) {
      m[k] = A.get_element(i+1, j+1);
      k++;
    }
  }
}


int main (int argc, char* const argv[]) {
  cout << "9x9 identity matrix:" << endl;
  MyMatrix* m = new MyMatrix(9);
  m->print();

  cout << "   rows: " << m->get_rows() << ", ";
  cout << "columns: " << m->get_columns() << endl;

  delete m;


  cout << endl << "2x5 matrix:" << endl;
  MyMatrix n(2,5);
  n.print();

  cout << "   rows: " << n.get_rows() << ", ";
  cout << "columns: " << n.get_columns() << endl;

  cout << "(1,3) = " << n.get_element(1,3) << endl;

  cout << "last: (2,5) = " << n.get_element(2,5) << endl;

  cout << "second to last element = 100: " << endl;
  n.set_element(2, 4, 100);
  n.print();

  cout << endl << "addition:" << endl;
  cout << "matrix 1:" << endl;
  MyMatrix* a1 = new MyMatrix(3,3);
  a1->print();
  cout << "matrix 2:" << endl;
  MyMatrix* a2 = new MyMatrix(3,3);
  a2->print();
  cout << "result:" << endl;
  MyMatrix* e1 = new MyMatrix(3,3);
  *e1 = *a1+*a2;
  e1->print();
  delete e1;

  cout << endl << "multiplication" << endl;
  cout << "matrix 1:" << endl;
  MyMatrix* m1 = new MyMatrix(3,3);
  a1->print();
  cout << "matrix 2:" << endl;
  MyMatrix* m2 = new MyMatrix(3,3);
  m2->print();
  cout << "result:" << endl;
  MyMatrix* e2 = new MyMatrix(3,3);
  *e2 = *m1 * *m2;
  e2->print();
  delete e2;

  return 0;
}