expected initializer before '&' token error

[vipul mehta]

I have made a header file as follows;

class float16 {
public:
float mantissa;
long double expo;

float16 operator+(float16);
float16 operator-(float16);
float16 operator/(float16);
float16 operator*(float16);
};

extern float16 add (float16* const, float16);
extern float16 sub (float16* const, float16);
extern float16 div (float16* const, float16);
extern float16 mul (float16* const, float16);
extern istream& operator >> (istream&, float16&);
extern ostream& operator << (ostream&, float16&);

it gives error that it requires an initializer for the lines containing istream and ostream.

How can i remove that?

[kbw]

Are you missing using namespace std;?