Re: precision

[Peter Hermann <ica2ph@iris16.csv.ica.uni-stuttgart.de>]

>> What is precision of float means?
>> My understanding is that if precision is 6 digits then 1.0 and
>> 1.0000001 are same!!! Please let me know whether my understanding is
   1 23456 = decimal position
>> right.If not then what it means?
> Approximately. For exact information, see RM 3.5.7.

and more (-:
The compiler is required to map the mantissa to AT LEAST 10 decimal 
digits, which means for binary representation a binary mantissa
of at least 6/lg2 = 6/0.301... = 19.93... giving AT LEAST 
20 binary digits.
However the chosen mantissa length depends very much on the implementation.
On 32bit floating point you may have a 23 or 24 bit mantissa where as
on a 60 or 64 bit smallest floating point (e.g. CDC, Cray)
your smallest mantissa has 48 bits.
In this case 1.0 and 1.0000001 will be "different" :-)

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