Experimental Physics and Industrial Control System
Tim Mooney wrote:
To this end, does anyone happen to know the precedence and associativity of these
operators? I.e.,
does a + b <? c mean (a + b) <? c or a + (b <? c)
does a <? b <? c mean (a <? b) <? c or a <? (b <? c)
does a * b <? c mean (a * b) <? c or a * (b <? c)
etc. I haven't been able to find this information online.
I've been doing some testing using g++ 3.2.2, here are my results:
Minimum operator <? precedence
------------------------------
a <? b * c means a <? (b * c)
a <? b + c means a <? (b + c)
a <? b << c means a <? (b << c)
a <? b < c means a <? (b < c)
a <? b == c means a <? (b == c)
a <? b & c means (a <? b) & c
a <? b ^ c means (a <? b) ^ c
Which inserts <? between == and & on the precedence table. Also:
a == b <? c means (a == b) <? c
a & b <? c means a & (b <? c)
shows that <? isn't on the same line as either == or &.
Maximum operator >? precedence
------------------------------
a >? b == c means a >? (b == c)
a >? b & c means (a >? b) & c
a == b >? c means (a == b) >? c
a & b >? c means a & (b >? c)
So this also fits between == and & and is not on the same line as either.
Relative precedence and associativity
-------------------------------------
a >? b <? c means (a >? b) <? c
a <? b >? c means (a <? b) >? c
Thus the two have the same precedence, and are left-to-right associative.
This confirms experimentally the result that Noboru found by looking at
the g++ source code.
- Andrew
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