RosettaCodeData/Task/Digital-root/C/digital-root.c

27 lines
475 B
C

#include <stdio.h>
int droot(long long int x, int base, int *pers)
{
int d = 0;
if (pers)
for (*pers = 0; x >= base; x = d, (*pers)++)
for (d = 0; x; d += x % base, x /= base);
else if (x && !(d = x % (base - 1)))
d = base - 1;
return d;
}
int main(void)
{
int i, d, pers;
long long x[] = {627615, 39390, 588225, 393900588225LL};
for (i = 0; i < 4; i++) {
d = droot(x[i], 10, &pers);
printf("%lld: pers %d, root %d\n", x[i], pers, d);
}
return 0;
}