Compile error when defining overloaded friend operator?

[mwatson]

Hey I'm trying to compile a project for class (C++/linux) but I can't figure out what this g++ error means:

time.h:22: error: ISO C++ forbids declaration of 'istream' with no type
time.h:22: error: 'istream' is neither function nor member function; cannot be declared friend
time.h:22: error: expected ';' before '&' token

The code it's referencing is a public function definition:

#include <iostream>

class Time
{
  private:
    int hour, minute;
    bool am;
    Time() {};
    friend class Appointment;

  public:
    Time(int, int, bool);
    int getHour();
    int getMinute();
    bool isAM();
    bool operator<(Time);
    [B]friend istream& operator>>(istream& istr, Time t);[/B]
};

Shouldn't istream be defined in the iostream header file?

Thanks in advance for any help, and let me know if more info is needed.

[mwatson]

Dumb mistake on our part - forgot the using namespace std;