🚀 go-pugleaf

On Wed, 18 Sep 2002 02:02:04 GMT, "Mike K" <mkipper@rogers.com> wrote:

>Hi,
>
>To start off, yes this is a school question. The question is as follows:
>Write a C++ program to calculate and print the square root of an integer to
>40 decimal points.

Can you choose the integer yourself?  In that case, calculate and write
out the square root of 4.  Limit yourself to integers, and assert that
the computed integer square root is a precise square root.

Hth.,

- Alf

<cough>...array...<cough>....


"Mike K" <mkipper@rogers.com> wrote in message
news:w8Rh9.77700$561.55900@news02.bloor.is.net.cable.rogers.com...
> Hi,
>
> To start off, yes this is a school question. The question is as follows:
> Write a C++ program to calculate and print the square root of an integer
to
> 40 decimal points.
> To me, this seems like a Newton's Method type problem, except for the fact
> that my computer can't do more than MSVC++'s 80-bit/10-byte long double.
> So, I was thinking of writing a template class which holds BCD number
> information in nibbles (full bytes for now, optimize later). Then, math is
> performed through the nibble array.
> Is this sane? Is there a better way to do it? I don't want to waste my
time
> reinventing the wheel, if there's already a better answer out there.
> I did find, through my travels, a library called BigInt.h, which kind of
> implements the same kind of idea:
>
> #define BIGINT_TOTAL_BITS 128       // Produces 38   decimal digits
> #define BIGINT_BASE_BITS 32         // Number of bits in base type
> #define BIGINTSIZE (BIGINT_TOTAL_BITS / BIGINT_BASE_BITS)
> typedef unsigned long BIGINT_BASE;  // The base type.
> public:
>   BIGINT_BASE data[BIGINTSIZE];     /* Little endian data */
>
> But I couldn't get it to work properly.
>
> Thanks for your help!
>
> Michael
> -----
>
>
>

Howdy!

> Is this sane? Is there a better way to do it? I don't want to waste my time
> reinventing the wheel, if there's already a better answer out there.
> I did find, through my travels, a library called BigInt.h, which kind of
> implements the same kind of idea:

Well I recall seeing another bit of code to do this:

http://www.snippets.org/snippets/portable/portable.php3, under
"Cliff Rhodes' package of unsigned integer math for arbitrarily large
numbers"

For all I know it's the same as "BigInt", and I haven't got a clue if
it works or not.  But it might be worth a look.

Cheers
  Richard

Try this site:

http://www.perfsci.com/free/giantint/index.html

Download the file at "click here". Open up tutor.c and examine the code.
They basically used an array. Check out their giants.h header file too.


"Mike K" <mkipper@rogers.com> wrote in message
news:w8Rh9.77700$561.55900@news02.bloor.is.net.cable.rogers.com...
> Hi,
>
> To start off, yes this is a school question. The question is as follows:
> Write a C++ program to calculate and print the square root of an integer
to
> 40 decimal points.
> To me, this seems like a Newton's Method type problem, except for the fact
> that my computer can't do more than MSVC++'s 80-bit/10-byte long double.
> So, I was thinking of writing a template class which holds BCD number
> information in nibbles (full bytes for now, optimize later). Then, math is
> performed through the nibble array.
> Is this sane? Is there a better way to do it? I don't want to waste my
time
> reinventing the wheel, if there's already a better answer out there.
> I did find, through my travels, a library called BigInt.h, which kind of
> implements the same kind of idea:
>
> #define BIGINT_TOTAL_BITS 128       // Produces 38   decimal digits
> #define BIGINT_BASE_BITS 32         // Number of bits in base type
> #define BIGINTSIZE (BIGINT_TOTAL_BITS / BIGINT_BASE_BITS)
> typedef unsigned long BIGINT_BASE;  // The base type.
> public:
>   BIGINT_BASE data[BIGINTSIZE];     /* Little endian data */
>
> But I couldn't get it to work properly.
>
> Thanks for your help!
>
> Michael
> -----
>
>
>

B Summers wrote:
> 
> Try this site:
> 
> http://www.perfsci.com/free/giantint/index.html
> 
> Download the file at "click here". Open up tutor.c and examine the code.

I did that. Here's the first thing I found:

void
main(
        void
)
{

I'm not convinced that the code is worth further study.

-- 
Richard Heathfield : binary@eton.powernet.co.uk
"Usenet is a strange place." - Dennis M Ritchie, 29 July 1999.
C FAQ: http://www.eskimo.com/~scs/C-faq/top.html
K&R answers, C books, etc: http://users.powernet.co.uk/eton