unsigned long long int to long double

[Daniel Rudy]

How does one covert a interger number in a unsigned long long int
(64-bit) to long double (80-bit) storage? I looked at math.h and I
found function that convert double to long long, but didn't really see
anything that I could use.

 

[Peter Nilsson]

How does one covert a interger number in a unsigned long long int
(64-bit) to long double (80-bit) storage?

my_long_double = my_unsigned_long_long_int;

I looked at math.h and I found function that convert double to long
long, but didn't really see anything that I could use.

Which function are you talking about?

Note, if the bit size of your types actually matter, then comp.lang.c
is probably not the best group to post to; you would be better off
asking a platform/compiler specific group.

 

[Daniel Rudy]

At about the time of 9/18/2005 8:42 PM, Peter Nilsson stated the following:

my_long_double = my_unsigned_long_long_int;

It's that easy? Whoa...Thanks.

Which function are you talking about?
sqrt();

Note, if the bit size of your types actually matter, then comp.lang.c
is probably not the best group to post to; you would be better off
asking a platform/compiler specific group.

I know that the interger type matters because it's a counter. I'm not
sure about the floating point type though.

 

[Barry Schwarz]

At about the time of 9/18/2005 8:42 PM, Peter Nilsson stated the following:


It's that easy? Whoa...Thanks.


sqrt();

sqrt doesn't convert anything, let alone double to long long. sqrt
returns a double. sqrtl returns a long double.

I know that the interger type matters because it's a counter. I'm not
sure about the floating point type though.

The fact that it is a counter only matters if you are counting things
in excess of 2+ billion. Possible if you are working with stars in
galaxies or grains of sand but why do you think the bit size matters?


<<Remove the del for email>>

 

[Daniel Rudy]

At about the time of 9/18/2005 11:48 PM, Barry Schwarz stated the following:

sqrt doesn't convert anything, let alone double to long long. sqrt
returns a double. sqrtl returns a long double.

The code in question is this:

rstats.tavg = acc1 / count;
rstats.tvar = (acc2 / count) - (rstats.tavg * rstats.tavg);
rstats.tdev = sqrt(rstats.tvar);

This code takes values that were collected earlier and computes average,
variance, and standard deviation. The acc1 and acc2 variables are
defined as uint64 (unsigned long long int) while everything else is
defined as a ldfloat (long double). I do need a square root function,
but I used sqrt as a place holder until I can find the sqrt function
that I really need. I do thank you for telling me that sqrtl returns a
long double.

The fact that it is a counter only matters if you are counting things
in excess of 2+ billion. Possible if you are working with stars in
galaxies or grains of sand but why do you think the bit size matters?

It probably doesn't, but I threw those numbers in there anyways. The
real questions were how to convert a unsigned long long int to a long
double, and if there was a sqrt function that returned a long double.

 

[Peter Shaggy Haywood]

Groovy hepcat Daniel Rudy was jivin' on Mon, 19 Sep 2005 05:49:28 GMT
in comp.lang.c.
Re: unsigned long long int to long double's a cool scene! Dig it!

At about the time of 9/18/2005 8:42 PM, Peter Nilsson stated the following:

sqrt();

You mean the sqrt() function that has the following signature?

double sqrt(double);

You mean the sqrt() function that returns the square root of its
input? You mean you really think this function converts a double to a
long long?
Tell me, is there insanity in your family?

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