Question

Is there a way to convert a mpz_t variable to unsigned long long in C?How about the other way around,from ull to mpz_t?The gmp library doesn’t support this as ull are part of C99.
I found this but it’s in c++,and I don’t know how to code in c++.Thanks in advance.

Answer 1

Here are some functions for translating between unsigned long long and mpz_t. Note that mpz2ull will smash your stack if the number is too big to fit into an unsigned long long:

unsigned long long mpz2ull(mpz_t z)
{
    unsigned long long result = 0;
    mpz_export(&result, 0, -1, sizeof result, 0, 0, z);
    return result;
}

void ull2mpz(mpz_t z, unsigned long long ull)
{
    mpz_import(z, 1, -1, sizeof ull, 0, 0, &ull);
}