Magnanimous numbers: Difference between revisions

=={{header|C}}==

{{trans|Go}}

<lang c>#include <stdio.h>

#include <string.h>

typedef int bool;

typedef unsigned long long ull;

#define TRUE 1

#define FALSE 0

// OK for 'small' numbers.

bool is_prime(ull n) {

ull d;

if (n < 2) return FALSE;

if (!(n % 2)) return n == 2;

if (!(n % 3)) return n == 3;

d = 5;

while (d * d <= n) {

if (!(n % d)) return FALSE;

d += 2;

if (!(n % d)) return FALSE;

d += 4;

}

return TRUE;

}

void ord(char *res, int n) {

char suffix[3];

int m = n % 100;

if (m >= 4 && m <= 20) {

sprintf(res,"%dth", n);

return;

}

switch(m % 10) {

case 1:

strcpy(suffix, "st");

break;

case 2:

strcpy(suffix, "nd");

break;

case 3:

strcpy(suffix, "rd");

break;

default:

strcpy(suffix, "th");

break;

}

sprintf(res, "%d%s", n, suffix);

}

bool is_magnanimous(ull n) {

ull p, q, r;

if (n < 10) return TRUE;

for (p = 10; ; p *= 10) {

q = n / p;

r = n % p;

if (!is_prime(q + r)) return FALSE;

if (q < 10) break;

}

return TRUE;

}

void list_mags(int from, int thru, int digs, int per_line) {

ull i = 0;

int c = 0;

char res1[13], res2[13];

if (from < 2) {

printf("\nFirst %d magnanimous numbers:\n", thru);

} else {

ord(res1, from);

ord(res2, thru);

printf("\n%s through %s magnanimous numbers:\n", res1, res2);

}

for ( ; c < thru; ++i) {

if (is_magnanimous(i)) {

if (++c >= from) {

printf("%*llu ", digs, i);

if (!(c % per_line)) printf("\n");

}

}

}

}

int main() {

list_mags(1, 45, 3, 15);

list_mags(241, 250, 1, 10);

list_mags(391, 400, 1, 10);

return 0;

}</lang>

{{out}}

<pre>

First 45 magnanimous numbers:

0 1 2 3 4 5 6 7 8 9 11 12 14 16 20

21 23 25 29 30 32 34 38 41 43 47 49 50 52 56

58 61 65 67 70 74 76 83 85 89 92 94 98 101 110

241st through 250th magnanimous numbers:

17992 19972 20209 20261 20861 22061 22201 22801 22885 24407

391st through 400th magnanimous numbers:

486685 488489 515116 533176 551558 559952 595592 595598 600881 602081

</pre>