How to make '

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What does the >?= operator mean?

I found this code segment

...
for(k=i+1;k<j;k++) r <?= go(i,k,b)+go(k,j,b);
for(k='A';k<='Z';k++) r <?= 1+go(i,j,k);
...

I'm interested in <?= operator. It seems to me that it should compare value of r with right side of the operator and in case that right side is greater than r it should assign right side to r. I would like to know where are this (and similar operators, I suppose) defined and what should I do make them available for use with g++ compiler?

It's a pity that this doesn't have a standard operator. I use this type of assignment so often that I tend to include it as a member function `numclass::push_downto(const numclass &)` in number-like classes, but that's not really good style and you can't do it at all for plain primitive types. — leftaroundabout, May 21 '11 at 01:07
It was the minimum assginment operator, the value was assigned if the right side was smaller — Gunther Piez, May 21 '11 at 01:31

score 16 · Accepted Answer · edited May 23 '17 at 11:55

16

The <?= operator was a GCC extension that was removed in version 4.2. See this question.

Use std::min instead.

edited May 23 '17 at 11:55

Community

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answered May 21 '11 at 00:47

hammar

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score 2 · Answer 2 · answered May 21 '11 at 00:47

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I don't think that this is a valid C++ operator

answered May 21 '11 at 00:47

George Kastrinis

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Not standard, but an extension. – Lightness Races in Orbit May 21 '11 at 00:48
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@Tomalak: ... so it's not a valid *standard* C++ operator. This doesn't deserve a downvote. – Matteo Italia May 21 '11 at 00:53
It's a perfectly valid C++ operator. If the answer correctly specified standard vs extension, it would be correct. And, for what it's worth, I did not downvote it. – Lightness Races in Orbit May 21 '11 at 01:54
Extensions are called extensions because they extend the language. They are not the language. – George Kastrinis May 21 '11 at 01:57

score 0 · Answer 3 · answered May 21 '11 at 00:47

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Not doable. The operators that C++ supports are fixed, you can't add new ones.

answered May 21 '11 at 00:47

Andrew

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Implementation extensions can. – Lightness Races in Orbit May 21 '11 at 00:48
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GCC is *NOT* C++. The standard doesn't define such an operator. – George Kastrinis May 21 '11 at 00:51
"C++" can be read as "standard C++" or "practical C++". Without the qualifier, it's ambiguous. – Lightness Races in Orbit May 21 '11 at 01:55

How to make '

3 Answers3