Re: Overload Operators for referenced objects?

From:
Rolf Magnus <ramagnus@t-online.de>
Newsgroups:
comp.lang.c++
Date:
Sun, 11 Feb 2007 19:27:13 +0100
Message-ID:
<eqnn61$23r$02$1@news.t-online.com>
Jonas Huckestein wrote:

hello,

somehow i can't figure out, how to overload the [] operator for a
referenced object. if i have

class MyClass {

int operator[](int i) { return 1; };

};

...

MyClass* oskar = new MyClass();
cout << oskar[3];
delete oskar;

the compiler says "cannot convert ???OperatorSequence??? to ???int??? in
initialization".


The compiler probably wants to say that it can't find an operator << that
takes a MyClass object. oskar[3] ist the same as *(oskar+3), expecting that
oskar is the pointer to the start of an array of MyClass, and you wan the
3rd element of that array.

with

MyClass oskar;

it works, though. how can i use the overloaded [] for pointers?


You are using it, but I guess you actually don't want to. If you want to use
the [] operator of your class instead of the one for pointers, you have to
dereference first:

cout << (*oskar)[3];

i also need to overload arithmetic operations in my class, is there a
similar problem when dealing with referenced objects?


Well, if you use a pointer, the operators for pointers will be used.

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