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Re: increasing var twice in a statement
Chris Wolstenholme wrote:
1) The statement was a = ++b + ++b;
2) b=3 before this statement
3) The operator ++ on the right hand side of the + operator is executed
first by rules of precedence. As it is pre-increment, b becomes 4.
... yielding a (hypothetical) temporary holding the value 4 as the right
hand operand of "+".
4)The operator ++ on the left hand side of the + operator is then
executed. As it is also pre-increment, b is again altered to become 5.
... yielding a(nother hypothetical) temporary holding the value 5 as the
left hand operand of "+".
5) Then the operator + is executing adding b (now 5) to b (still 5).
... which would yield 9 (= 5 + 4) according to the above.
That's only two increments of b, but both before the addition operator.
Try to derive a syntax tree from the expression and evaluate it by
walking that tree using your defined order and you'll arrive at a = 9.
Cheers,
Christian