[fpc-pascal] type conversions
Jonas Maebe
jonas at zeus.rug.ac.be
Mon Dec 9 11:27:11 CET 2002
On maandag, dec 9, 2002, at 11:19 Europe/Brussels,
memsom at interalpha.co.uk wrote:
> Um, unsigned... this will always equate to 0 if the count is 0 because
> an
> *unsigned* number can _only_ hold positive numbers (0..n, *not* -n..(n
> -1)). So
> 0 -1 can only be 0 because 0 is the smallest number the variable can
> hold.
No, a type conversion between ordinal types does not change one bit
pattern into another. -1 is a bit pattern that only contains 1-bits, so
when you convert that to an unsigned type, it still contains only
1-bits and as such becomes the highest value that that unsigned type
can represent (65535 in case of an unsigned 16 variable).
Jonas
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