RosettaCodeData/Task/Left-factorials/C/left-factorials.c
2023-07-01 13:44:08 -04:00

50 lines
954 B
C

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <gmp.h>
void mpz_left_fac_ui(mpz_t rop, unsigned long op)
{
mpz_t t1;
mpz_init_set_ui(t1, 1);
mpz_set_ui(rop, 0);
size_t i;
for (i = 1; i <= op; ++i) {
mpz_add(rop, rop, t1);
mpz_mul_ui(t1, t1, i);
}
mpz_clear(t1);
}
size_t mpz_digitcount(mpz_t op)
{
/* mpz_sizeinbase can not be trusted to give accurate base 10 length */
char *t = mpz_get_str(NULL, 10, op);
size_t ret = strlen(t);
free(t);
return ret;
}
int main(void)
{
mpz_t t;
mpz_init(t);
size_t i;
for (i = 0; i <= 110; ++i) {
if (i <= 10 || i % 10 == 0) {
mpz_left_fac_ui(t, i);
gmp_printf("!%u = %Zd\n", i, t);
}
}
for (i = 1000; i <= 10000; i += 1000) {
mpz_left_fac_ui(t, i);
printf("!%u has %u digits\n", i, mpz_digitcount(t));
}
mpz_clear(t);
return 0;
}