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

Discussion in 'C++' started by Mamut, Feb 21, 2007.

1. ### MamutGuest

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
?
Mamut, Feb 21, 2007

2. ### Victor BazarovGuest

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?
Victor Bazarov, Feb 21, 2007

3. ### MamutGuest

> Have you tried googling for those?

yes but for this polynomials I can't find...
Mamut, Feb 21, 2007
4. ### Victor BazarovGuest

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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Victor Bazarov, Feb 21, 2007
5. ### MamutGuest

>
> 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.
Mamut, Feb 22, 2007
6. ### Victor BazarovGuest

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 5.8).

V
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