Iccanobif primes: Difference between revisions
Added C
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26 -> 4898934056...4215909399 (1947 digits)
27 -> 1274692768...7994940101 (2283 digits)</pre>
=={{header|C}}==
{{trans|Wren}}
{{libheader|GMP}}
There's a big jump in digit count between the 29th and 30th numbers and consequently the latter is very slow indeed to emerge.
<syntaxhighlight lang="c">#include <stdio.h>
#include <string.h>
#include <gmp.h>
char *reverse(char *s) {
int i, j, len = strlen(s);
char t;
for (i = 0, j = len - 1; i < j; ++i, --j) {
t = s[i];
s[i] = s[j];
s[j] = t;
}
return s;
}
int main() {
int count = 0;
size_t len;
char *s, a[44];
mpz_t fib, p, prev, curr;
mpz_init(fib);
mpz_init(p);
mpz_init_set_ui(prev, 0);
mpz_init_set_ui(curr, 1);
printf("First 30 Iccanobif primes:\n");
while (count < 30) {
mpz_add(fib, curr, prev);
s = mpz_get_str(NULL, 10, fib);
mpz_set_str(p, reverse(s), 10);
if (mpz_probab_prime_p(p, 15) > 0) {
++count;
s = mpz_get_str(NULL, 10, p);
len = strlen(s);
if (len > 40) {
strncpy(a, s, 20);
strcpy(a + 20, "...");
strncpy(a + 23, s + len - 20, 21);
}
printf("%2d: %s (%ld digits)\n", count, len <= 40 ? s : a, len);
}
mpz_set(prev, curr);
mpz_set(curr, fib);
}
mpz_clear(fib);
mpz_clear(p);
mpz_clear(prev);
mpz_clear(curr);
return 0;
}</syntaxhighlight>
{{out}}
<pre>
Same as Wren example.
</pre>
=={{header|jq}}==
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