Thread: Subtracting a decimal value from a Char?

  1. #1
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    May 2021

    Subtracting a decimal value from a Char?

    I'm looking at Muller's Micro-Max chess engine, trying to port it to z80 ASM just as a fun challenge.
    While I consider myself well-versed in z80 as a hobby, I have little experience with C.

    I'm looking at this line of code:

    If I'm correct, L was / has been declared as a variable of "char" type. So I'm confused about subtracting 3.5 from a "char" variable. Let's say that K = 7 and L = 7. What would the result be?

  2. #2
    and the hat of int overfl Salem's Avatar
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    Aug 2001
    The edge of the known universe
    L will be promoted to double for that part of the calculation, which will result in the whole right hand side being promoted to double for evaluation.
    The assignment will then truncate the whole thing back to char.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

  3. #3
    Registered User
    Join Date
    May 2021
    Thanks, that answers my question and fixes the problem.

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