Velocity Reviews > C++ > crc-8 and crc-16 code...

# crc-8 and crc-16 code...

Mamut
Guest
Posts: n/a

 02-21-2007
Hello
Does have anybody procedures for:
CRC-8: polynomial x^8 + x^7 + x^2 + 1
i CRC-16: polynomial x^16 + x^15 + x^2 + 1
?

Victor Bazarov
Guest
Posts: n/a

 02-21-2007
Mamut wrote:
> Does have anybody procedures for:
> CRC-8: polynomial x^8 + x^7 + x^2 + 1
> i CRC-16: polynomial x^16 + x^15 + x^2 + 1
> ?

Have you tried googling for those?

Mamut
Guest
Posts: n/a

 02-21-2007

> Have you tried googling for those?

yes but for this polynomials I can't find...

Victor Bazarov
Guest
Posts: n/a

 02-21-2007
Mamut wrote:
>> Have you tried googling for those?

>
> yes but for this polynomials I can't find...

If you just need to calculate polynomials, what's the problem?
Write a function that takes your argument and multiplies and

// 'n' = degree, 'a' = array of factors (sized n+1)
// 'x' = parameter
double polynomial(double x, double *a, size_t n)
{
double result = a[n];
while (n) {
result *= x;
result += a[--n];
}
return result;
}

Now, all you need is to define the proper arguments...

V
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Mamut
Guest
Posts: n/a

 02-22-2007

>
> If you just need to calculate polynomials, what's the problem?
> Write a function that takes your argument and multiplies and

no, I need to calculate CRC sum based on these polinomials and I can't
do this.

Victor Bazarov
Guest
Posts: n/a

 02-22-2007
Mamut wrote:
>> If you just need to calculate polynomials, what's the problem?
>> Write a function that takes your argument and multiplies and

>
> no, I need to calculate CRC sum based on these polinomials and I can't
> do this.

This sound like an admission of defeat. What seems to be the problem?
Do you have the algorithm? If yes, have you attempted to convert it
into C++ terms? If yes, do you get compiler errors? If yes, read the
FAQ 5.8. If you don't have the algorithm, we can't help you. Try
posting to comp.programming or search for it on the web. Once you
find the algorithm, try writing it down in C++ terms. If you don't
succeed (and how would you know unless the compiler complains, right?),
post what you have and the errors (IOW, follow the recommendations of
FAQ 5..

V
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