Trouble with input/output operator overloading

[hyrkas]

Hello there,

I'm working on an assignment for my C++ class at my university. One part of the assignment is to write a Complex number class to learn to learn about operator overloading (hence writing the class, as opposed to simply using c++'s built in Complex number class).

I've got the +, -, and * operators working correctly, but I'm having trouble with the << and >> operators for input and output. Here's the relevant code:

Complex.h:

#ifndef COMPLEX_H_INCLUDE
#define COMPLEX_H_INCLUDE
#include <iostream>

/*! \file Complex.h: Declares the Complex number class
Author: Jeremy Hyrkas
*/

class Complex {

public:

Complex (double r = 0, double i = 0) : real(r), imaginary(i) {}

inline void setReal(double r) { real = r;}
inline void setImaginary(double i) {imaginary = i;}
inline double getReal () const {return real;}
inline double getImaginary () const {return imaginary;}
double getMagnitude () const;

protected:

double real;
double imaginary;
};

Complex operator+ ( const Complex& lhs, const Complex& rhs);
Complex operator- ( const Complex& lhs, const Complex& rhs);
Complex operator* ( const Complex& lhs, const Complex& rhs);
ostream& operator<< ( ostream& out, const Complex& value);
istream& operator>> ( istream& in, Complex& value);

#endif // COMPLEX_H_INCLUDE


Complex.cpp:

#include <Complex.h>
#include <math.h>

double getMagnitude () const {
double magnitude = ((real * real) + (imaginary * imaginary));
return sqrt (magnitude);
}

Complex operator+ ( const Complex & lhs, const Complex & rhs) {
return Complex (lhs.getReal() + rhs.getReal(), lhs.getImaginary() + lhs.getImaginary());
}

Complex operator- ( const Complex & lhs, const Complex & rhs) {
return Complex (lhs.getReal() - rhs.getReal(), lhs.getImaginary() - lhs.getImaginary());
}

Complex operator* ( const Complex & lhs, const Complex & rhs) {
double r = (lhs.getReal() * rhs.getReal()) + ((-1) * lhs.getImaginary() * rhs.getImaginary());
double i = (lhs.getReal() * rhs.getImaginary()) + (lhs.getImaginary() * rhs.getReal());

return Complex (r, i);
}

ostream& operator<< ( ostream& out, const Complex& value) {
out << real << " " << value.imaginary;
return out;
}

istream& operator>> ( istream& in, Complex& value) {
double r = 0, i = 0;

in >> r;
in >> i;
value.setReal(r);
value.setImaginary(i);

return in;
}


main.cpp:

#include <Complex.h>
using std::cout;

int main (int argc, char* argv[]) {
//NO OP FOR NOW
}


I'm compiling with g++:

g++ -I. -Wall main.cpp

And the error I receive is:

./Complex.h:30: error: expected constructor, destructor, or type conversion before '&' token
./Complex.h:31: error: expected constructor, destructor, or type conversion before '&' token

I believe it's a problem with the function head of my << and >> functions. However, I've modeled them after a similar example in my textbook, and I've also looked at examples online, and the function heads look identical. If anyone has any ideas what I'm doing syntactically wrong, I'd appreciate it.

Thank you,

Jeremy H.

[helios]

istream and ostream are in the std namespace.

[hyrkas]

Thanks! That was an easy fix. I did find another problem though...

I changed my main to a simple:

#include <Complex.h>
using std::cout;

int main (int argc, char* argv[]) {

Complex com = Complex(4, 4);
cout << com << endl;
}

But now I'm getting the following error:

/tmp/ccuKH5Cr.o: In function `main':
main.cpp:(.text+0x93): undefined reference to `operator<<(std::basic_ostream<char, std::char_traits<char> >&, Complex const&)'
collect2: ld returned 1 exit status

How do I get "cout << com" to reference the << operator that I wrote for Complex?

[hyrkas]

Ha, shoot, never mind. I was just compiling main.cpp and not Complex.cpp. Stupid mistake.

Thanks again.