What is the fastest way of getting the fraction part of a floating point?

[ME]

What is the fastest way of getting the fraction part of a floating point
number?

So, if I have a float 10.3 I want to get a float with value 0.3 fast.

Thanks

[roberts.noah@gmail.com]

Re: What is the fastest way of getting the fraction part of a floating point?


ME wrote:[color=blue]
> What is the fastest way of getting the fraction part of a floating point
> number?
>
> So, if I have a float 10.3 I want to get a float with value 0.3 fast.
>
> Thanks[/color]

x - static_cast<int >(x);

[Jerry Coffin]

Re: What is the fastest way of getting the fraction part of a floating point?

ME wrote:[color=blue]
> What is the fastest way of getting the fraction part of a floating point
> number?
>
> So, if I have a float 10.3 I want to get a float with value 0.3 fast.[/color]

Look up modf().

--
Later,
Jerry.

[Tom]

Re: What is the fastest way of getting the fraction part of a floating point?

On Thu, 2 Feb 2006 20:13:09 +0100, "ME" <me@home.com> wrote:
[color=blue]
>What is the fastest way of getting the fraction part of a floating point
>number?
>
>So, if I have a float 10.3 I want to get a float with value 0.3 fast.
>
>Thanks
>
>
>[/color]
From MS help. Convert to C++ style if you like.
Use 1.0 as the "y" number to get the fractional part.

double x = div(10.3, 1.0);
// result: x = 0.3;

/* DIV.C: This example takes two integers as command-line
* arguments and displays the results of the integer
* division. This program accepts two arguments on the
* command line following the program name, then calls
* div to divide the first argument by the second.
* Finally, it prints the structure members quot and rem.
*/

#include <stdlib.h>
#include <stdio.h>
#include <math.h>

void main( int argc, char *argv[] )
{
int x,y;
div_t div_result;

x = atoi( argv[1] );
y = atoi( argv[2] );

printf( "x is %d, y is %d\n", x, y );
div_result = div( x, y );
printf( "The quotient is %d, and the remainder is %d\n",
div_result.quot , div_result.rem );
}


Output

x is 876, y is 13
The quotient is 67, and the remainder is 5

[JE]

Re: What is the fastest way of getting the fraction part of a floating point?

Tom wrote:[color=blue]
> On Thu, 2 Feb 2006 20:13:09 +0100, "ME" <me@home.com> wrote:
>[color=green]
> >What is the fastest way of getting the fraction part of a floating point
> >number?
> >
> >So, if I have a float 10.3 I want to get a float with value 0.3 fast.
> >
> >Thanks
> >
> >
> >[/color]
> From MS help. Convert to C++ style if you like.
> Use 1.0 as the "y" number to get the fractional part.
>
> double x = div(10.3, 1.0);
> // result: x = 0.3;[/color]

< snip >

That's not going to work. First of all, div returns a div_t or ldiv_t
struct. Second of all, div takes two ints or two longs as arguments
(double is trouble!). In your case, the remainder of the div_t return
div_t::rem would be 0...

[Tom]

Re: What is the fastest way of getting the fraction part of a floating point?

On 2 Feb 2006 13:08:33 -0800, "JE" <jericson@pacbe ll.net> wrote:
[color=blue]
>Tom wrote:[color=green]
>> On Thu, 2 Feb 2006 20:13:09 +0100, "ME" <me@home.com> wrote:
>>[color=darkred]
>> >What is the fastest way of getting the fraction part of a floating point
>> >number?
>> >
>> >So, if I have a float 10.3 I want to get a float with value 0.3 fast.
>> >
>> >Thanks
>> >
>> >
>> >[/color]
>> From MS help. Convert to C++ style if you like.
>> Use 1.0 as the "y" number to get the fractional part.
>>
>> double x = div(10.3, 1.0);
>> // result: x = 0.3;[/color]
>
>< snip >
>
>That's not going to work. First of all, div returns a div_t or ldiv_t
>struct. Second of all, div takes two ints or two longs as arguments
>(double is trouble!). In your case, the remainder of the div_t return
>div_t::rem would be 0...[/color]

Ouch. I was Totally Wrong !!

Modf is the ticket. I think I need a nap.