#ifndef MATRIXH
#define MATRIXH
#include <iostream>
#include <cstdlib>
using namespace std;

void error(const char* s);

class Matrix{
  // This is a row x col matrix
 int row, col;
 double *m;

public:
 Matrix(int r , int c=1);       // constructors & destructor
 Matrix(const Matrix& );
 ~Matrix(){delete [] m;};

 inline double& operator()(int i, int j){ // external store & read
   return (m[i*col + j]);};

 Matrix& operator=( const Matrix& B){   // *this=B
   // note that this does not follow the standard form for
   // writing assignment operators. Instead it says it is
   // an error to write A = B unless A & B have the same size.

   if( row!=B.row || col!=B.col) error("Matrix=: incompatible sizes");
   int i, rc = row*col;
   for( i=0; i<rc; i++ ) m[i] = B.m[i];
   return *this;
 };

 // friends can access private data
 friend Matrix operator+(const Matrix&, const Matrix&);
 friend Matrix operator*(const Matrix&, const Matrix&);
 friend Matrix operator-(const Matrix&, const Matrix&);
 friend Matrix operator*(double, const Matrix&);
 friend Matrix operator&(const Matrix&, const Matrix&);
 friend ostream& operator<<(ostream&,Matrix);
 friend Matrix transpose(const Matrix&);
 friend Matrix solve(const Matrix&, const Matrix&);
};

Matrix operator*( const Matrix& A, double a);
#endif