Hello, Alexander
======= 2006-12-04 21:29:06 Alexander wrote =======
>But is there any reason to change while() {} to do {} while()? I think we
>should
>check pNextAddr && (numAddresses<maxAddresses) right after we have got
>first pNextAddr:
>PIP_ADDR_STRING pNextAddr = &pNextInfoRecord->IpAddressList;
= = = = = = = = = = = = = = = = = = = =
Generally speeking, while(){} is safer than do {} while() and while() {} will
certainly work in this case.
Well, in this case, while(){} and do{}while() do the same thing. I can prove
that.
Right after "PIP_ADDR_STRING pNextAddr = &pNextInfoRecord->IpAddressList;" and
just before entering the inner loop, (numAddresses<maxAddresses) is always
true, since it has been checked in the outer loop: while (pNextInfoRecord &&
(numAddresses<maxAddresses)). And the address of
(pNextInfoRecord->IpAddressList) is not NULL. So pNextAddr must NOT be NULL. It
then follows that (pNextAddr && (numAddresses<maxAddresses)) is always true
when we first enter the inner loop, thus concludes that while(){} and
do{}while() do the same thing in this case.
The reason why i preffer do{}while() than while(){} is that usually compiler
may generate one more conditional jump instruction if while(){} is used. But in
this case, we won't see the difference in performance whether we use
do{}while() or we use while(). Both will work well.
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