[Note: please do not top-post: it makes conversations harder to follow]
yes...only last 10 digits....
In your original posting, you said 8, and this time you said 10,
which just happens to be the number of digits after the decimal point
that I gave. What is the "rule" -- the last 8 digits before the
deciminal point if the fractional part is 0, and the first 10 digits
after the decimal point of the fractional part is non-0 ??
You do realize, I hope, that as you get into larger values
such as 123456789012345 that the representation as a float is
inexact? For example on the system I happen to be using:
(dbx) p (float) 123456789012345
123456788103168.0
Notice that the last 7 places do not agree with the original number.
Unless there is something you haven't told us about that -greatly-
restricts the values of the float, then float is not at all a good
choice for representation of numbers when particular interior positions
are more important than magnitude.