Extremely large numbers in c++

[Todd.Branchflower]

Hey everyone,

I am new to c++ and the group and would appreciate your help.

I was doing a problem on projecteuler.net in which you had to find the
largest factor of an extremely large number. Unfortunately, I didn't
know how to accommodate a number of this size in c++. After
developing my algorithm and writing it in c++, I wrote the program in
ruby (a bit easier for large numbers) and found the answer. Looking
in the forum at other people's code, I was able to change mine to
work:

#include <iostream>
#include <cmath>
using namespace std;

int main() {

long long N=317584931803LL;

for (long long int i=2; i<=sqrt(N); i++) if (!(N%i)) N/=i;

cout << N;

string wait;

cin >wait;

return 0;
}
My question is, what is the significance of the LL convention
following the number?? Why won't the code work without it? Also,
some people didn't need the LL when they declared N as __int64. This
doesn't work on my compiler (Dev-C++), as the compiler says the number
is too large for the __int64 data type. Why? Final question, how can
I compile programs at the command line with Dev-C++?

Thanks in advance for your help,
Todd

[Victor Bazarov]

James Kanze wrote:

On Dec 31 2007, 5:43 pm, "Victor Bazarov" <[e-mail]>
wrote:

>[e-mail] wrote:

>>I am new to c++ and the group and would appreciate your help.

[...]

[.. doctorate thesis on something that is *not* in C++ *now* ..]

If on the 1st of January, you're spending time correcting somebody
else's answers on Usenet, you need to get a life. Seriously.

Happy New Year!

V
--
Please remove capital 'A's when replying by e-mail
I do not respond to top-posted replies, please don't ask

[jacob navia]

To***************@gmail.com wrote:

Hi Todd.

If you do not mind using plain C (with some C++ like operator
overloading) you should use lcc-win, a free compiler for windows.

It features 352 bits floating point, 128 bit integers, true
long double (80 bits) and other goodies. It has too an
extensive math library.

Download it at the URL below

--
jacob navia
jacob at jacob point remcomp point fr
logiciels/informatique
http://www.cs.virginia.edu/~lcc-win32