Rounding Question

[Mikael Olofsson]

I corrected Remco:
 >  I'm sorry, but this also behaves badly. It rounds 10 up to 20. To get
 >  Jacob's desired functionality, you could modify your idea to
 >  
 >    rounded = number-((number-1)%10)+9
 >  
 >  still assuming only integer input.


Alex Martelli wrote:
 >  ...which of course is totally equivalent to the earlier
 >  proposed
 >      rounded = (number+9) - ((number+9)%10)
 >  since addition is commutative and associative (you can
 >  move the +9 from the right of the expression) AND so
 >  is addition in modulo-arithmetic, so that:
 >  
 >  (X-1)%N==(X%N)+((-1)%N)==(X%N)+((N-1)%N)==(X+N-1)%N

Of course! I just couldn't stay silent when Remco stumbled again.

/Mikael

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E-Mail:  Mikael Olofsson <mikael at isy.liu.se>
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Date:    22-Feb-01
Time:    14:35:06

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