trying my hand using class in computing matrices, but in writing my base class i keep getting 1 warning and 2 errors: cannot convert char to in, not seeing the reason, 2 how to use friend class...

class matrix
    {
      public:

	// these are overloaded operators - 3 styles
	void operator = (const matrix);
	float * operator() (const int, const int) ;

	// this is a constructor function
	matrix (int m, int n)  // default initialization
	  {
	     rows = m;      //set the members
	     cols = n;
	     pt = new float[rows*cols];
	  }
	// these are the variable members - they are private
      private:
	int rows, cols;
	float *pt;
      };    // note the ;

  // overloaded definitions
  void matrix :: operator =(const matrix arg)
      {
	 int i;
	 if( (rows != arg.rows) || (cols != arg.cols) )
	   {
	     cout <<  "\n You cannot set different sized";
	     cout << " matrices equal to each other. \n";
	     //exit(EXIT_FAILURE);
	   }

	 for (i=0; i < rows*cols; i++)
	   *(pt+i) = *(arg.pt+i);
      }
  float * matrix :: operator() ( const int row, const int col)
      {
	 return pt + (row * cols + col);
      }

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

   // We can run with variable matrix size without re-compiling
   if (argc != 3)    // the program name and 2 variables = 3
     {
       cout << "You must include 2 values with the name of the program\n"
	    << " matrix #rows #cols. \n "
	    << " Try again.\n";
      // exit (EXIT_FAILURE);
     }

   int rows = (argv[1]);   // I trust that the user
   int cols = (argv[2]);   // will input good values

   matrix A(rows, cols);
   matrix B(rows,cols);
   matrix C(rows-2,cols-2);

   for (i=0; i < rows; i++)
     for (j=0; j < cols; j++)
       *A(i,j) = i + j;

   B = A;

   cout << "\n The A matrix \n";
   for (i=0; i < rows; i++)
     {
       for (j=0; j < cols; j++)
	 cout << *A(i,j) << "  ";
       cout << "\n";
     }

   cout << "\n The B matrix \n";
   for (i=0; i < rows; i++)
     {
       for (j=0; j < cols; j++)
	 cout << *B(i,j) << "  ";
       cout << "\n";
     }

   C = A;

  }