Xref: utzoo comp.lang.c++:12137 comp.std.c++:717
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From: ersys!markt@nro.cs.athabascau.ca (Mark Tarrabain)
Newsgroups: comp.lang.c++,comp.std.c++
Subject: Re: distinguishing operator[] on left and right
Message-ID: <FPHky2w163w@ersys.uucp>
Date: 10 Mar 91 00:25:38 GMT
References: <1991Mar6.235058.3641@osceola.cs.ucf.edu>
Organization: Edmonton Remote Systems, Edmonton, AB, Canada
Lines: 36

ssd@engr.ucf.edu (Steven S. Dick) writes:

> What if I have a [] operator that does something unusual to extract the
> data from the object... for instance, a bitfield...
> 
> // interface parts only...
> class packedbits 
> {
>  public:
>   packedbits(int size);
>   int operator[](int index);
>   void set(int index);
>   void clear(int index);
> };
> 
> doit() 
> {
>    packetbits flags(100);
> 
>    if (flags[4])	// this works
>      ....
> 
>    flags.set(4);	// works--but ugly
>    flags[4] = 1;	// how can I make this work???
> }
> 
> 	Steve
> ssd@engr.ucf.edu

The line reading:
        int operator[](int index);
should be:
        int &operator[](int index);
then it will work on the left or the right side of an =.

>> Mark