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Forum Index : Microcontroller and PC projects : Printing unsigned integers
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thwill Guru  Joined: 16/09/2019 Location: United KingdomPosts: 3830 |
Hi folks, I've been having a mental block on this one for 24 hours, even though it feels a bit like a standard interview problem you might ask a graduate programmer. I want an algorithm to print the unsigned integer corresponding to a negative signed 32 bit integer, e.g. given -254 it will print "4294967042" (a number larger than can be held by a signed 32 bit integer.) The rub is you only have: 32 bit integers Signed 32-bit arithmetic Logical shifts Single character printing, i.e. putchar(ch) Ideally the algorithm would print in an arbitrary base 2 .. 36, but I would settle for base 10 at the moment. Can anyone help, or point me at a reference? Best wishes, Tom Edited 2021-03-07 18:11 by thwill Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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jirsoft Guru Joined: 18/09/2020 Location: Czech RepublicPosts: 532 |
Hi Tom, I will simply start so (for negative number, so bit 31 set) last = inputValue MOD base last = (256 + last) MOD base inputValue = inputValue / base Now you have already inputValue in smaller range (so it can be used same as positive value), you will convert it to base and on the end output also last. I think this can work... Jiri Napoleon Commander and SimplEd for CMM2 (GitHub), CMM2.fun |
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| thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 3830 |
Thanks Jiri, I've finessed it for the moment by breaking some of the restrictions, but I will definitely look ath this when I get a moment. Best wishes, Tom Edited 2021-03-08 02:05 by thwill Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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