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Re: Burned by precedence rules

by swampyankee (Parson)
on Dec 24, 2008 at 04:26 UTC ( #732408=note: print w/replies, xml ) Need Help??

in reply to Burned by precedence rules

Like toolic, I work on the principle of "when in doubt, parenthesize." I've also dealt with optimizing compilers that would handle something like

do i = 1, 10 do j = 1, 10 do k = 1, 10 l = i + j + k enddo enddo enddo

differently from

do i = 1, 10 do j = 1, 10 do k = 1, 10 l = (i + j) + k enddo enddo enddo

in that it would not recognize i + j as constant in the innermost loop in the first fragment, but would in the second. There are also cases where I've needed to force a specific order of operations to preclude under or overflow.

I also won't rule out the possibility that, unlike the compiler, I can get confused about logical tests that have multiple and's, or's, and not's; using (perhaps superfluous) parentheses will reduce my confusion.

Information about American English usage here and here. Floating point issues? Please read this before posting. — emc

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