Re: Floating point

["Joseph Manning" <manning@...>]

On 2015-Oct-29 (Thu) at 17:16 (+0000), iain morland wrote:

>> If I assign a variable to the result of 23.2/0.2, and print that variable,
>> Lua outputs 116.	
>> 
>> However if I then use the same variable as the limit in an iterator,
>> the iterator stops on the 115th repeat, rather than the 116th as expected.
>> 
>> So it therefore seems that the variable is a floating point number
>> between 115 and 116. 
>> 
>> I don't understand why I can't print the floating point value of this
>> variable. I haven't rounded or truncated it, so why does it print
>> exactly 116, even though that's not its value?

Iain,

   $ lua53
   Lua 5.3.1  Copyright (C) 1994-2015 Lua.org, PUC-Rio
   > string.format( "%17.13f", 23.2/0.2 )
   116.0000000000000
   > string.format( "%18.14f", 23.2/0.2 )
   115.99999999999999

Joseph

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Joseph Manning / Computer Science / UCC Cork Ireland / manning@cs.ucc.ie
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