Simple atof() question

[Doug Gwyn]

In article <1214 at caslon.cs.arizona.edu> armstron at cs.arizona.edu (Jim Armstrong) writes:
>How can I get atof() to return a float instead of a double? 

You can't; it always returns type "double".

>When I run this simple program I get n = 37.549999 instead of
>n = 37.55.  What am I doing wrong?

That's a different question.  There's nothing particularly wrong with
your program, other than failing to return a value from main().  Note
that the float argument to printf() is promoted to a double, but that's
not a problem.

I think your real problem is that you think that the value 37.55 can
be represented exactly in a binary floating-point representation.
Somewhere along the way, probably within atof(), you're picking up a
small amount of "dirt" in the last bit or so of the internal
representation.  This is usual for floating-point; you should learn
from this to not expect exactness when floating-point is involved.