Re: Very simple question

From:

Jerry Coffin <jcoffin@taeus.com>

Newsgroups:

comp.lang.c++

Date:

Mon, 10 Sep 2007 22:18:15 -0600

Message-ID:

<MPG.214fc4f071f88c239899d1@news.sunsite.dk>

In article <1189428205.280920.285540@r34g2000hsd.googlegroups.com>,
DenisSolovov@gmail.com says...

I have very simple question, look at next expression:
int b = 0;
int c = 0;
int d = b+++++c;

Due to the 'maximum munch" rule, this is lexed as:

int d = b ++ ++ + c;

Since the first '++' returns an rvalue, the second one can't work, and
the expression doesn't compile.

If you want to be perverse, you can define a type for which ++ returns
an lvalue, and allow similar code to compile for that type:

class EVIL_LEAKY {
    int value;
public:
    EVIL_LEAKY(int v=0) : value(v) {}

    EVIL_LEAKY &operator++(int) {
        EVIL_LEAKY *temp = new EVIL_LEAKY;
        temp->value=value;
        value++;
        return *temp;
    }
    operator int() { return value; }
};

#ifdef TEST
#include <iostream>

int main() {
    EVIL_LEAKY b=0;
    EVIL_LEAKY c=0;
    int d = b+++++c;

    std::cout << "d=" << d << "\n";
    return 0;
}
#endif

As you might guess from its name, this class is definitely NOT an
example of recommended practice!

--
    Later,
    Jerry.

The universe is a figment of its own imagination.