Hi Sherif, I changed the example as follows. Thank you for your comment.
[yohgaki@dev en]$ svn diff Index: language/operators.xml =================================================================== --- language/operators.xml (リビジョン 330982) +++ language/operators.xml (作業コピー) @@ -225,15 +225,16 @@ <![CDATA[ <?php $a = 3 * 3 % 5; // (3 * 3) % 5 = 4 +// ternary operator associativity differs from C/C++ $a = true ? 0 : true ? 1 : 2; // (true ? 0 : true) ? 1 : 2 = 2 $a = 1; $b = 2; $a = $b += 3; // $a = ($b += 3) -> $a = 5, $b = 5 -// mixing ++ and + produces undefined behavior +// mixing ++ and + $a = 1; -echo ++$a + $a++; // may print 4 or 5 +echo ++$a + $a++; // same as ++$a; echo $a + $a; $a++; ?> ]]> </programlisting>