[prog] Overloading operator<<

[Sue Stones]

Compiler errors have been added below the repective code.
sue

On Tue, 10 Jun 2003 05:48 pm, Sue Stones wrote:
> I am trying to write an function to define << for the class widgit, but I
> can't get it to compile.  What am I doing wrong.  Below are a couple of the
> options that I have tried, I have copied the class definition and the
> problem function only!
>
> sue
>
> ------attempt1-----------
>
> #include <iostream>
> #include <strings.h>
> using std::cout;
> using std::endl;
>
> class Widgit {
> private:
>         int id_num;
>         char *description;
> public:
>         Widgit() {} // default constructor
>         Widgit(int id, char * desc ); // init constructor
>         Widgit(const Widgit& w); // copy constructor
>         Widgit& operator= (const Widgit& w); // define assignment for
> Wigits ostream& operator<< (ostream&, const Widgit&);
> 					 // define ostream << for Wigits
> };//widget
>
> ostream& operator<< (ostream& out, const Widgit& w){
>         out << w.id_num << ": "
>                 << w.description << endl;
>         return out;
> }  // define ostream << for Wigits


g++     Widgit.C   -o Widgit
Widgit.C:15: syntax error before `&' token
Widgit.C:39: syntax error before `&' token
make: *** [Widgit] Error 1
[

g++     Widgit.C   -o Widgit
Widgit.C:7: ISO C++ forbids declaration of `ostream' with no type
Widgit.C:7: `ostream' is neither function nor member function; cannot be 
declared friend
Widgit.C:7: parse error before `&' token
Widgit.C:39: syntax error before `&' token
make: *** [Widgit] Error 1
[

> ------attempt 2-----------
>
> #include <iostream>
> #include <strings.h>
> using std::cout;
> using std::endl;
>
> class Widgit {
> friend ostream&
> 	operator<< (ostream&, const Widgit&); // define ostream << for Wigits
> private:
>         int id_num;
>         char *description;
> public:
>         Widgit() {} // default constructor
>         Widgit(int id, char * desc ); // init constructor
>         Widgit(const Widgit& w); // copy constructor
>         Widgit& operator= (const Widgit& w); // define assignment for
> Wigits
>
> };//widget
>
> ostream& Widgit::operator<< (ostream& out, const Widgit& w){
>         out << w.id_num << ": "
>                 << w.description << endl;
>         return out;
> }  // define ostream << for Wigits
>

g++     Widgit.C   -o Widgit
Widgit.C:7: ISO C++ forbids declaration of `ostream' with no type
Widgit.C:7: `ostream' is neither function nor member function; cannot be 
declared friend
Widgit.C:7: parse error before `&' token
Widgit.C:39: syntax error before `&' token
make: *** [Widgit] Error 1


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