Collatz's conjecture + GMP games

collatz.c

#include <stdio.h>
#include <gmp.h>

int main() {
    mpz_t x, y, odd_or_even;
    mpz_init(x);
    mpz_init(y);
    mpz_init(odd_or_even);
    
    unsigned long int i, p;

    for (p = 69; p < 100000; p++) {
        mpz_ui_pow_ui(x, 2, p);
        mpz_sub_ui(x, x, 1);
        mpz_set(y, x);
        i = 0;
        while (1) {
            i += 1;
            mpz_mod_ui(odd_or_even, y, 2);
            if (mpz_get_ui(odd_or_even)) {
                mpz_mul_ui(y, y, 3);
                mpz_add_ui(y, y, 1);
            } else {
                mpz_cdiv_q_ui(y, y, 2);
            }
            if (mpz_cmp_ui(y, 1) == 0)
                break;
            else if (mpz_cmp(y, x) == 0)
                goto finish; // optimism!
        }
        printf("%lu %lu\n", p, i);
    }

finish:
    printf("%lu ", p);
    mpz_out_str(stdout, 10, y);
    printf(" %lu\n", i);

    mpz_clear(x);
    mpz_clear(y);
    mpz_clear(odd_or_even);

    return 0;
}

collatz_rand.c

#include <stdio.h>
#include <time.h>
#include <gmp.h>

int main() {
    gmp_randstate_t state;
    gmp_randinit_default(state);
    gmp_randseed_ui(state, time(NULL));

    mpz_t x, y, odd_or_even;
    mpz_init(x);
    mpz_init(y);
    mpz_init(odd_or_even);

    unsigned long int i;
    
    while (1) {
        mpz_urandomb(x, state, 1000);
        mpz_set(y, x);
        i = 0;
        while (1) {
            i += 1;
            mpz_mod_ui(odd_or_even, y, 2);
            if (mpz_get_ui(odd_or_even)) {
                mpz_mul_ui(y, y, 3);
                mpz_add_ui(y, y, 1);
            } else {
                mpz_cdiv_q_ui(y, y, 2);
            }
            if (mpz_cmp_ui(y, 1) == 0)
                break;
            else if (mpz_cmp(y, x) == 0)
                goto finish; // optimism!
        }
        //printf(" %lu\n", i);
    }

finish:
    mpz_out_str(stdout, 10, y);
    printf(" %lu\n", i);

    mpz_clear(x);
    mpz_clear(y);
    mpz_clear(odd_or_even);

    return 0;
}