Max int size now available?

mongrel666 · 05-01-2011, 05:59 PM

Hi, nice Noob with Noob question.
I am doing prime number research and I need to know what the max int size is? Does gcc support any other number declarations that would be better than just plain old int (this is in C BTW) that allow for integer handling??

Thanks in advance,

Jason.

plpl303a · 05-01-2011, 09:02 PM

Unsigned ints (uint32_t) are up to 2**32 - 1 (a little over 4 billion).
A long long (or uint64_t) is up to 2**64 - 1 (~18 quintillion)

If you want arbitrary precision arithmetic, check out gmp (http://gmplib.org/)

mongrel666 · 05-02-2011, 01:43 AM

Awesome!
I have this crappy little athalon Semperon laptop which is my dedicated Prime Number calculator and it just crapped its pants when it saw "quintillion"...

winning · 05-02-2011, 02:36 AM

The maximum int value is INT_MAX as defined by limits.h

plpl303a · 05-02-2011, 10:06 PM

Quote:

Originally Posted by winning

The maximum int value is INT_MAX as defined by limits.h

Yes, indeed; that will be the limit for signed ints. UINT_MAX will give you the maximum size for unsigned integers; LLONG_MAX for signed long longs (64 bits) and ULLONG_MAX for unsigned long longs.