Где ошибка? Работа с класами

#include <iostream.h>
#include <assert.h>
 
using namespace std;
 
class complex
 {
 double re,im;
 
 public:
 complex(double=0,double=0);
 ~complex();
 complex operator+(complex&);
 complex operator-(complex&);
 complex operator*(complex&);
 complex operator/(complex&);
 complex operator^(unsigned);
 friend istream& operator>>(istream&,complex&);
 friend ostream& operator<<(ostream&,complex&);
 };
 
  complex::complex(double r, double i)
  {
  re=r;
  im=i;
  }
  
  complex::~complex(){}
 
  complex complex::operator+(complex& y)
  {
  return complex(re+y.re,im+y.im);
  }
 
  complex complex::operator-(complex& y)
  {
  return complex(re-y.re,im-y.im);
  }
  
  complex complex::operator*(complex& y)
  {
  return complex(re*y.re-im*y.im,re*y.im+im*y.re);
  }
 
  complex complex::operator/(complex& y)
  {
  double r1=re;
  double i1=im;
  double r2=y.re;
  double i2=y.im;
  return complex((r1*r2-i1*i2)/(r2*r2+i2*i2),(-r1*i2+i1*r2)/(r2*r2+i2*i2));
  }
 
  complex complex::operator^(unsigned n)
  {
  complex y(1,0);
  for(int i=1;i<=n; i++)
  y=y*(*this);
  return y;
  }
 
  istream& operator>>(istream& is,complex& x)
  {
  char c;
  cin>>c;
  assert(c=='(');
  cin>>x.re;
  cin>>c;
  assert(c==',');
  cin>>x.im;
  cin>>c;
  assert(c==')');
  return is;
  }
 
  ostream& operator<<(ostream& os,complex& x)
  {
  os<<'('<<x.re<<','<<x.im<<')'<<'\n';
  return os;
  }
 
  void main()
  {
  complex a(1,1);
  complex b(1,1);
  complex c(1,1);
  complex x;
  cout<<"->";
  cin>>x;
  cout<<"Result= "<<a*(x^2)+b*x+c<<'\n';
  system("pause");
  }

class complex
 {
 double re,im;
 
 public:
 complex();
 complex operator*(complex&);
 complex operator^(unsigned);
 };
 
  int main()
  {
  complex x;
  x = x*(x^2);
  return 0;
  }