Thread: GMP Problem

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I realize in normal c++ you should do int array[4000000000], but in gmp doesn't the mpz_t_array_init make it an array for you? I fiddled around a bit and fixed the code so that it has no compile errors, but it has link errors now
Link errors are so annoying...unlike compiler errors you don't get specific lines, and the LNK2001 entry in MSDN encomposes a whole lot of possible problems, compile errors are much more specific about what's going wrong.
Anyways, the error is
error LNK2001: unresolved external symbol "class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,struct __mpz_struct const *)" (??6@YAAAV?$b
asic_ostream@DU?$char_traits@D@std@@@std@@AAV01@PB U__mpz_struct@@@Z)
I have no idea what that's talking about.
The error is for this code:

Code:

#include <iostream>
#include <gmp.h>

using namespace std;

int main()
{
	mpz_t n, N, N2, hold;
	bool array[100000000];
	int k=2, var;
	mpz_init (n);
	mpz_init (hold);
	mpz_init (N);
	mpz_init (N2);
	mpz_set_ui (n, 1000);
	mpz_sqrt (N, n);
	if (mpz_cmp_ui (N, 100000000) == -1)
		mpz_set_ui (N2, 100000000);
	else
		mpz_set (N2, N);
	while (mpz_cmp_ui (N2, k) == 1)
	{
		if (array[k] == 1)
		{
			mpz_cdiv_q_ui (hold, n, k);
			if (mpz_sgn (hold) == 0)
			{
			cout << k << " * " << hold << "; ";
			var = k;
			while (mpz_cmp_ui(N2, k) == 1)
			{
				var = var + k;
				array[var] = 0;
			}
			}
		}
		k++;
	}
	mpz_clear (n);
	mpz_clear (N);
	mpz_clear (N2);
	return 0;
}

Is anyone willing to help?
Thanks either way,
MadCow

I think it means that the << operator hasn't been overloaded for the mpz_t class. Therefore, when you try to call << to ouptput hold in the following line, there is no function/operator for the linker to find eventhough it is correct syntax so it compiles.


cout << k << " * " << hold << "; ";

To test if that's the problem comment out the line, and if the error goes away put a ; after the "*" and comment out the rest of the line. If you can narrow it down that way you will have confirmed what and where the problem is. To fix it you'll need to know what's in mpz_t so you can overload the << operator or so you can use some existing method of the mpz_t class to output information.