Re: Multiple operator overloading

From:

Saeed Amrollahi <amrollahi.saeed@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Sun, 7 Nov 2010 04:31:40 -0800 (PST)

Message-ID:

<31191cbc-6c7a-4074-805e-8364d11358d8@n10g2000prj.googlegroups.com>

On Nov 7, 3:17 pm, Andrea Crotti <andrea.crott...@gmail.com> wrote:

Looking on the internet looks like it's perfectly fine to overload
operators, but why then this doesn't work

--8<---------------cut here---------------start------------->8---
class Myclass
{
public:
int operator[](int index) { return 0; }
string operator[](int index) { string s = "ciao"; return s; }};

--8<---------------cut here---------------end--------------->8---

and gives the error
--8<---------------cut here---------------start------------->8---
try.cpp:23: error: =91std::string Myclass::operator[](int)' cannot be o=

verloaded

try.cpp:22: error: with =91int Myclass::operator[](int)'
--8<---------------cut here---------------end--------------->8---

It would be very useful in another case (thread Globals), how otherwise
I can achieve the same result?

The only other way coming to my mind is another class with a template
parameter and then specializing it for the different types, but it
sounds a bit too much for such a simple thing...

Hi Andrea
You can't overload two functions that are different just in return
type. It is
a general concept in "Function-name overloading":
  void f(int);
  int f(int); // error: only they are different in return types
Same applies to overloaded operators.

Regards,
  -- Saeed Amrollahi