Re: overloading of ","

From:
red floyd <no.spam@here.dude>
Newsgroups:
comp.lang.c++
Date:
Mon, 12 Mar 2007 20:29:04 GMT
Message-ID:
<kKiJh.4728$yW.4570@newssvr11.news.prodigy.net>
josh wrote:

Hi, I coded the following but It does not return what I expect, why?

#include <iostream>

using namespace std;

class Other
{
public:
    int i;

    Other(int x=1)
    {
        i = x;
    }

    Other *operator-> () { return this;}

    Other &operator+ (Other t)
    {
        i += t.i;

        return *this;
    }

    Other &operator,(Other oth)
    {
        i = oth.i;

        return *this;
    }

};

int main()
{
    Other o0, o1, o2(4), o3(5);

    o0->i = 100;

    cout << o0.i << "\n" << o0->i << "\n";

       // HERE it returns 5 AND not 6 WHY ???????????????????
    Other ox = (o1 + o1, o3 = o2 + o1);
       // ------------------
    cout << ox.i << endl;

    return 0;
}


You are modifying and evaluating the same object (o1) between sequence
points. Your program's behavior is therefore undefined.

Please see the FAQ on ++i,i++, and following (39.15 and 39.16)

http://www.parashift.com/c++-faq-lite/misc-technical-issues.html#faq-39.15

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