operator difference

[stef]

Hello,
Could you tell me the difference between

char &operator[](int idx)
{
return tab[idx];
}

and

char operator[](int idx)
{
return tab[idx];
}



Thanks...

 

[Victor Bazarov]

Could you tell me the difference between

char &operator[](int idx)
{
return tab[idx];
}

and

char operator[](int idx)
{
return tab[idx];
}

The sixth symbol, '&' (called "ampersand"). Makes the return
value type different.

V

 

[Tomás Ó hÉilidhe]

Could you tell me the difference between

char &operator[](int idx)
{
return tab[idx];
}

and

char operator[](int idx)
{
return tab[idx];
}

The one that returns a reference can be used as an L-value (in an
assignment for instance).

my_obj[5] = 77;

 

[Abhishek Padmanabh]

Hello,
Could you tell me the difference between

char &operator[](int idx)
{
return tab[idx];
}

and

char operator[](int idx)
{
return tab[idx];
}

If they were members of a class - they would cause overload ambiguity.
You would declare the second one as const member, and first one as non-
const. That is how random access is implemented for std::vector/
std::string etc. Of course, for them the argument idx is not a signed
int. It would be their specific size_type, for example: implementation
defined typedef for an unsigned integral type.

The second one returns by value, so a copy is returned.