#include <iostream>
#include <iomanip>

class matrix
{
  protected:
    int rows, cols;
    int * data;

  public:
    matrix(int numrows, int numcols)
    { rows = numrows;
      cols = numcols;
      data = new int [rows*cols]; }

    int numrows()
    { return rows; }

    int numcols()
    { return cols; }

  protected:
    int pos(int r, int c)
    { if (r<0 || r>=rows || c<0 || c>=cols)
      { cout << "error accessing [" << r << "][" << c << "] when range is "
             << "[0 to " << rows-1 << "][0 to " << cols-1 << "]\n";
        return -1; }
      return r * cols + c; }

  public:
    int get(int r, int c)
    { int p = pos(r, c);
      if (p == -1)
        return 0;
      return data[p]; }

    void set(int r, int c, int newval)
    { int p = pos(r, c);
      if (p == -1)
        return;
      data[p] = newval; }
};

void print(matrix & M)       // ALWAYS use a reference parameter for any object that
{ int rows = M.numrows(),    // anything created by "new".
      cols = M.numcols();
  for (int r = 0; r < rows; r += 1)
  { for (int c = 0; c < cols; c += 1)
      cout << " " << setw(3) << M.get(r, c);
    cout << "\n"; } }

void main()
{ matrix timestable(12, 12);

  for (int x = 1; x <= 12; x += 1)
    for (int y = 1; y <= 12; y += 1)    // be careful: arrays run from 0 to max, but
      timestable.set(x-1, y-1, x*y);    // times-tableses go from 1 to 12.

  cout << "Behold the times-table\n\n";
  print(timestable);
  cout << "\nThat's that.\n"; }