#include <iostream.h>


// --------------------------------------------- MatrixNxN: Dynamic size matrix
class MatrixNxN
{
public:
   float *A;
   int    N;

   /* ------------------------------------------
      DEFAULT Constructor (assume n = 3)
      ------------------------------------------ */
   MatrixNxN()
   {
      int i, j;

      cout << "Calling DEFAULT constructor" << endl << endl;
      A = new float[3*3];
      for (i = 0; i < 3; i=i+1)
         for (j = 0; j < 3; j=j+1)
	    if (i == j)
	       A[i*3+j] = 1;
	    else
	       A[i*3+j] = 0;
      N = 3;
   }

   /* ------------------------------------------
      COPY Constructor
      ------------------------------------------ */
   MatrixNxN(MatrixNxN &x)
   {
      int i, j;

      cout << "Calling COPY constructor" << endl << endl;

      N = x.N;			// N is from the class (see above)
      A = new float[N*N];
      for (i = 0; i < N; i=i+1)
         for (j = 0; j < N; j=j+1)
	    A[i*N+j] = x.A[i*N+j];
   }

   /* ------------------------------------------
      Constructor(int)
      ------------------------------------------ */
   MatrixNxN(int n)
   {
      cout << "Calling constructor with n = " << n << endl << endl;
      A = new float[n*n];
      N = n;
   }

   /* ------------------------------------
      AddNum(x): add number to matrix
      ------------------------------------ */
   void AddNum(float x)
   {
      int i, j;

      for (i = 0; i < N; i = i + 1)
         for (j = 0; j < N; j = j + 1)       
            A[i*N+j] = A[i*N+j] + x;
   };

   /* ------------------------
      Print(): print matrix
      ------------------------ */
   void Print()
   {
      int i, j;

      for (i = 0; i < N; i = i + 1)
      {
         for (j = 0; j < N; j = j + 1)
            cout << A[i*N+j] << "\t";
         cout << "\n";
      }
      cout << "\n";
   };
};
// -----------------------------------------------------------------------




int main(int argc, char *argv[])
{
   int i, j, k, N;

   N = 4;

   MatrixNxN M(N);

   k = 1;
   for (i = 0; i < N; i = i + 1)
      for (j = 0; j < N; j = j + 1)
      {
         M.A[i*N+j] = k;
         k = k + 1;
      }

   M.Print();


   MatrixNxN Q(M);
   Q.Print();

   // ----------------------- See what happens when we change Q.A[0][0]
   Q.A[0] = 1234;

   cout << "After setting Q.A[0][0] = 1234: " << endl << endl;

   M.Print();
   Q.Print();
}