Programming Forums > Application Development > C++

Twilight · May 7th, 2006, 10:23 PM

To fix your >> operator, try something like the following:

istream& operator>>(istream& in)
{
   for(char ch = in.get(); ch != /* whatever you use for a delimiter */ && !in.fail(); ch = in.get()
      this.add(ch);
   return in;
}

That should allow operations to be performed using the "this" pointer created when the >> function was called.

Animatronic · May 7th, 2006, 10:34 PM

Twilight the <<, >> operators can't be member functions, as the class parameter needs to be on the right to be called correctly.

If you use your >> function you would have to call it up by doing something like:

(Toggle Plain Text)

Stash s;
s >> std::cin;

...which dosent make any sense at all.

Twilight · May 8th, 2006, 4:51 AM

Yeah, but when you actually write the class code, you just define the operator. Since the operator itself it just something performed on a class, the this pointer should still work.

Jimbo · May 8th, 2006, 5:33 AM

No. The operator could be a friend function (if access to private stuff is needed; it isnt in this case), but either way the operator is defined globally, so using the this pointer is invalid. Think about it: if you are writing main, and you suddenly use this->something(), does it make any sense?

btw, thanks to Animatronic for pointing out my typo :o

May 7th, 2006, 10:23 PM	#11
Twilight Programmer Join Date: Apr 2006 Location: Calgary, Alberta Posts: 67 Rep Power: 3	To fix your >> operator, try something like the following: (Toggle Plain Text) istream& operator>>(istream& in) { for(char ch = in.get(); ch != /* whatever you use for a delimiter / && !in.fail(); ch = in.get() this.add(ch); return in; } istream& operator>>(istream& in) { for(char ch = in.get(); ch != / whatever you use for a delimiter */ && !in.fail(); ch = in.get() this.add(ch); return in; } That should allow operations to be performed using the "this" pointer created when the >> function was called.

May 7th, 2006, 10:34 PM	#12
Animatronic Programmer Join Date: Jun 2005 Posts: 99 Rep Power: 4	Twilight the <<, >> operators can't be member functions, as the class parameter needs to be on the right to be called correctly. If you use your >> function you would have to call it up by doing something like: (Toggle Plain Text) Stash s; s >> std::cin; Stash s; s >> std::cin; ...which dosent make any sense at all.

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May 8th, 2006, 4:51 AM	#13
Twilight Programmer Join Date: Apr 2006 Location: Calgary, Alberta Posts: 67 Rep Power: 3	Yeah, but when you actually write the class code, you just define the operator. Since the operator itself it just something performed on a class, the this pointer should still work.

May 8th, 2006, 5:33 AM	#14
Jimbo Battle Programmer Join Date: Feb 2006 Location: Bellevue, WA, USA Posts: 769 Rep Power: 3	No. The operator could be a friend function (if access to private stuff is needed; it isnt in this case), but either way the operator is defined globally, so using the this pointer is invalid. Think about it: if you are writing main, and you suddenly use this->something(), does it make any sense? btw, thanks to Animatronic for pointing out my typo :o

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Programming Forums > Application Development > C++

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