pointer arthrmetic using operator overloading?

[Bharath]

Hello All,
Can you please let me know if we can do pointer arthrmetic using
operator overloading? If not, can you please explain why it's not
supported by compiler?

I tried below e.g. which was giving me error.

typedef class x
{
}X;
void operator +(X *p,X *q)
{
}
main()
{
X *p,*q;
p+q;
}

[/home/dbk/temp_eg]: gcc ptr.cpp
ptr.cpp:5: `operator +(X *, X *)' must have an argument of class or
enumerated type
ptr.cpp: In function `int main()':
ptr.cpp:10: invalid operands `X *' and `X *' to binary `operator +'
Any idea what are these errors?

TIA,
Bharath

[Thomas J. Gritzan]

Bharath wrote:

Hello All,
Can you please let me know if we can do pointer arthrmetic using
operator overloading? If not, can you please explain why it's not
supported by compiler?

You can only overload operators for user defined types (i.e. classes).
Pointers are predefined types.

--
Thomas
http://www.netmeister.org/news/learn2quote.html

[Rolf Magnus]

Bharath wrote:

Hello All,
Can you please let me know if we can do pointer arthrmetic using
operator overloading?

Yes. However, you cannot replace the built-in functionality for pointers
with a user-defined operator.

If not, can you please explain why it's not supported by compiler?

The idea of operator overloading is that you can extend the language, not
replace the existing functionality with different behavior. So you cannot
write yur own operators for built-in types, but only for user-defined ones.

I tried below e.g. which was giving me error.

typedef class x
{
}X;
void operator +(X *p,X *q)
{
}
main()
{
X *p,*q;
p+q;
}

[/home/dbk/temp_eg]: gcc ptr.cpp
ptr.cpp:5: `operator +(X *, X *)' must have an argument of class or
enumerated type

An operator must have at least one argument of user-defined type, and
pointers are built-in types.

ptr.cpp: In function `int main()':
ptr.cpp:10: invalid operands `X *' and `X *' to binary `operator +'

The compiler didn't accept your definition of operator +, so none is defined
at this point.

Btw: an operator+ that returns void is quite strange.