Polinomi

Salve, sto svolgendo un esercizio sui polinomi, volevo sapere perchè nel file header se scrivo Poly& Poly::operator=( const Poly& q ); mi dà come errore ' extra qualification for Poly:: on member operator = [f-permissive]' . Ho scritto ciò perchè nel file di implementazione attraverso questa dichiarazione ho poi scritto questo.

Poly& Poly::operator=( const Poly& q )
{
  if (this != &q)
  {
  delete [] coef;
  deg = q.getDeg();
  double *qcoef = q.getCoef();
  coef = new double[deg+1];
  for (int i=0; i<=deg; i++)
      coef[i] = qcoef[i];
  }

Qui l'intero codice:
poly.h

#include <iostream>
using namespace std;


class Poly {
private:
  int deg;
  double *coef;
public:
  Poly(void);
  Poly(int n, double *a);
  Poly( const Poly& q );

  Poly& Poly::operator=( const Poly& q );

  ~Poly(void);
  int getDeg(void) const;
  double *getCoef(void) const;
  Poly& scale( double k );
  Poly& shiftby( const Poly& q );
  double eval( double x )const;
  friend Poly operator+( const Poly& p, const Poly& q );
  friend Poly operator*( double k, const Poly& p );
  void print( char *nome ) const;
};

poly.cpp

* poly.cpp
 *
 *  Created on: 06/mag/2014
 *      Author: raffaele
 */

#include <iostream>
#include "poly.h"
using namespace std;

Poly::Poly( void )
{
  coef = new double[1];
  deg = 0;
  coef[0] = 0;
}

Poly::Poly( int n, double *a )
{
  deg = n;
  coef = new double[n+1];
  for (int i=0; i<=n; i++)
      coef[i] = a[i];
}

Poly::Poly( const Poly& q )  // copy constructor
{
  deg=q.getDeg();
  double *qcoef=q.getCoef();
  coef = new double[deg+1];
  for (int i=0; i<=deg; i++)
      coef[i] = qcoef[i];
}

Poly& Poly::operator=( const Poly& q )
{
  if (this != &q)
  {
  delete [] coef;
  deg = q.getDeg();
  double *qcoef = q.getCoef();
  coef = new double[deg+1];
  for (int i=0; i<=deg; i++)
      coef[i] = qcoef[i];
  }
  return *this;
}

int Poly::getDeg(void) const
{
  return deg;
}

double *Poly::getCoef(void) const
{
  return coef;
}

void Poly::print( char *nome ) const
{
  if (nome != NULL)
    cout << "Polinomio " << nome;
  cout << ":  grado = " << deg << ";  ";
  for (int i=0; i<=deg; i++)
    cout << "[" << i <<"]=" << coef[i] << ";  ";
  cout << '\n';
}

Poly::~Poly( void )
{
  delete [] coef;
}

Poly& Poly::scale( double k )
{
  for (int i = 0; i <= deg; i++)
    coef[i] *= k;
  return *this;
}

Poly& Poly::shiftby( const Poly& q )
{
  int i;
  if (q.deg > deg)
    {
      double *newvec = new double[q.deg+1];
      for (i=0; i<=q.deg; i++)
	newvec[i] = (i > deg)? 0: coef[i];
      delete [] coef;
      coef = newvec;
      deg = q.deg;
    }
  for (i = 0; i <= q.deg; i++)
    coef[i] += q.coef[i];
  return *this;
}

double Poly::eval( double x ) const
{
  double val = 0;
  for (int i = deg; i >= 0; i--)
    val = val*x+coef[i];
  return val;
}

Poly operator+( const Poly& p, const Poly& q )
{
  Poly temp(p);
  temp.shiftby( q );
  return temp;
}

Poly operator*( double k, const Poly& p )
{
  Poly temp(p);
  temp.scale( k );
  return temp;
}

mainpoly.cpp

#include <iostream>
#include "poly.h"
using namespace std;
int main()
{

  int i, n;
  double *temp, k;

  // leggiamo due polinomi

  cout << "assegna grado e coefficienti a_0, a_1, .., a_n di p\n ";
  cin >> n;
  temp = new double[n+1];
  for (i=0; i<=n; i++)
    cin >> temp[i];
  Poly p(n, temp);
  delete [] temp;
  p.print("p");
  cout << "p(1) = " << p.eval(1) << "\n";

  cout << "assegna grado e coefficienti b_0, b_1, .., b_n di q \n";
  cin >> n;
  temp = new double[n+1];
  for (i=0; i<=n; i++)
    cin >> temp[i];
  Poly q(n, temp);
  delete [] temp;
  q.print("q");
  cout << "q(1) = " << q.eval(1) << "\n";

  cout << "\nInizializzo r col valore 7*p+q e lo stampo\n";
  Poly r(7*p+q);
  r.print("r");
  cout << "\nDichiaro r1, gli assegno il valore p+q+r e lo stampo\n";
  Poly r1;
  r1 = p+q+r;
  r1.print("r1");

  cout << "\nStampo il polinomio 100*q\n";
  (100*q).print("100*q");

  cout << "\nMoltiplico q per 4 e lo stampo\n";
  q.scale(4.);      // scalo q di 4;
  q.print("q");     // e lo stampo

  cout << "\nSommo a p il polinomio q e stampo p\n";
  p.shiftby(q);    // sommo q in p e stampo p;
  p.print("p");

  return 0;
}