A problem with overloading << (compiler = djgpp)

[Tatu Portin]

1: #include <iostream>
2:
3: typedef struct {
4: double r;
5: double i;
6: } complex;
..
..
..
24: ostream & operator<< (ostream &str, const complex &a)
25: {
26: s << "(" << a.r << " + i" << a.i ")";
27: return s;
28: }

when compiled with gcc:
[color=blue]
>gcc complex.cc[/color]
complex.cc:24: syntax error before `&' token

I think this error has something to do with that 'ostream'. I have #included
<iostream>, so that should not cause this?

[John Harrison]

Re: A problem with overloading &lt;&lt; (compiler = djgpp)


"Tatu Portin" <axel86@mbnet.f i> wrote in message
news:3yR7d.96$X 94.42@read3.ine t.fi...[color=blue]
> 1: #include <iostream>
> 2:
> 3: typedef struct {
> 4: double r;
> 5: double i;
> 6: } complex;[/color]

That is C style code, its not wrong but in C++ we prefer

struct complex {
double r;
double i;
};
[color=blue]
> .
> .
> .
> 24: ostream & operator<< (ostream &str, const complex &a)
> 25: {
> 26: s << "(" << a.r << " + i" << a.i ")";
> 27: return s;
> 28: }
>
> when compiled with gcc:
>[color=green]
> >gcc complex.cc[/color]
> complex.cc:24: syntax error before `&' token
>
> I think this error has something to do with that 'ostream'. I have
> #included <iostream>, so that should not cause this?[/color]

You are forgetting that ostream is in the std namespace.

std::ostream & operator<< (std::ostream &str, const complex &a)

Also look at

using std::ostream;

or

using namespace std;

John

[Tatu Portin]

Re: A problem with overloading &lt;&lt; (compiler = djgpp)

Did help! Thank you, John!