Re: how to specify power of number


"Yanb" <Yanb@xxxxxxxxxxxxxxxx> wrote in message
news:fu9q89$kem$1@xxxxxxxxxxx
Hi, I'm new to c, so please excuse, if this is silly ;-)

I made a C function, which takes IP adress from string and converts to
unsigned long int. Everything
works, but I found that the "counting" part part works only with this:

numericip=atoi(textip[0])*256*256*256+atoi(textip[1])*256*256+atoi(textip[2])*256+atoi(textip[3]);

When I wrote *(256^3), I got fake results. I'd like to use something more
sophisticated, instead of 256*256
*256, which does look silly ;-) (Just curious, what if I'd ever need to
make 100th power of 256 ;-) )

You would have to use pow(256,3) which uses floating point arithmetic -- not
recommended, even though the compiler is likely to optimise.

Your code is fine as it is, the compiler will optimise 256*256*256 to
*16777216 or <<24. Or just write those in yourself.

--
Bart


.

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