Why do I get "error: declaration of ‘operator<<’ as non-function"?

[Michael Fox]

The following code won't compile with g++, instead giving me the error:
-----------------
prog2.cpp:36:33 : error: declaration of ‘operator<<’ as non-function
prog2.cpp:36:32 : error: expected ‘;’ before ‘(’ token
prog2.cpp: In function ‘int main()’:
prog2.cpp:49:12 : error: no match for ‘operator<<’ in ‘std::cout << z’
------------------

My code is below, it is a simple complex number class:

#include <iostream>
using namespace std;
 
class complex
{
private:
   double re, im; //real and imaginary parts
public:
   void set(double r, double i) {re = r; im = i;}
   complex() {set(0.0,0.0);}
   complex(double r, double i) {set(r,i);}
   complex(const complex &src)
      {re = src.re; im = src.im;}
   complex(double r) {set(r,0.0);}
 
   double get_re() const {return re;}
   double get_im() const {return im;}
   complex get_conj() const
      {complex c(re, -1.0*im); return c;}
   double get_mag_sq() const
      {double m = (re*re)+(im*im); return m;}
 
   complex add(const complex &other)
      {complex c(re+other.re,im+other.im); return c;}
   complex sub(const complex &other)
      {complex c(re-other.re,im-other.im); return c;}
   complex mult(const complex &other);
   complex div(const complex &other);
 
   complex operator+(const complex &other) {return add(other);}
   complex operator-(const complex &other) {return sub(other);}
   complex operator*(const complex &other) {return mult(other);}
   complex operator/(const complex &other) {return div(other);}
   bool operator==(const complex &other)
      {return re == other.re && im == other.im;}
   friend ostream &operator<<(osteam &os, complex &cplx);
};
 
int main()
{
   complex x(5.0,6.9);
   complex y(3.0,4.0);
   complex z = x*y;
   z = z/y;
 
   cout << x.get_re() << "+" << x.get_im() << "i" << endl;
   cout << z.get_re() << "+" << z.get_im() << "i" << endl;
   cout << (x == y) << endl;
   cout << z << endl;
 
   return 0;
}
 
complex complex::mult(const complex &other)
{
   complex c(re*other.re-im*other.im,re*other.im+im*other.re);
   return c; 
}
 
complex complex::div(const complex &other)
{
   complex c = (*this * other.get_conj())*(1/other.get_mag_sq());
   return c;
}
 
ostream &operator<<(ostream &os, complex &cplx)
{
   os << cplx.re << "+" << cplx.im << "i";
   return os;
}
 

[weaknessforcats]

The friend declaration has misspelled ostream as osteam.