Digital root/Multiplicative digital root: Difference between revisions

Content added Content deleted
(C solution addition.)
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8 :8 18 24 29 36
8 :8 18 24 29 36
9 :9 19 33 91 119</pre>
9 :9 19 33 91 119</pre>

=={{header|C}}==
<lang C>
#include <stdio.h>

#define twidth 5
#define mdr(rmdr, rmp, n)\
do { *rmp = 0; _mdr(rmdr, rmp, n); } while (0)

void _mdr(int *rmdr, int *rmp, long long n)
{
/* Adjust r if 0 case, so we don't return 1 */
int r = n ? 1 : 0;
while (n) {
r *= (n % 10);
n /= 10;
}

(*rmp)++;
if (r >= 10)
_mdr(rmdr, rmp, r);
else
*rmdr = r;
}

int main(void)
{
int i, j, vmdr, vmp;
const int values[] = { 123321, 7739, 893, 899998 };
const int vsize = sizeof(values) / sizeof(values[0]);

/* Initial test values */
printf("Number MDR MP\n");
for (i = 0; i < vsize; ++i) {
mdr(&vmdr, &vmp, values[i]);
printf("%6d %3d %3d\n", values[i], vmdr, vmp);
}

/* Determine table values */
int table[10][twidth] = { 0 };
int tfill[10] = { 0 };
int total = 0;
for (i = 0; total < 10 * twidth; ++i) {
mdr(&vmdr, &vmp, i);
if (tfill[vmdr] < twidth) {
table[vmdr][tfill[vmdr]++] = i;
total++;
}
}

/* Print calculated table values */
printf("\nMDR: [n0..n4]\n");
for (i = 0; i < 10; ++i) {
printf("%3d: [", i);
for (j = 0; j < twidth; ++j)
printf("%d%s", table[i][j], j != twidth - 1 ? ", " : "");
printf("]\n");
}

return 0;
}
</lang>
{{out}}
<pre>
Number MDR MP
123321 8 3
7739 8 3
893 2 3
899998 0 2

MDR: [n0..n4]
0: [0, 10, 20, 25, 30]
1: [1, 11, 111, 1111, 11111]
2: [2, 12, 21, 26, 34]
3: [3, 13, 31, 113, 131]
4: [4, 14, 22, 27, 39]
5: [5, 15, 35, 51, 53]
6: [6, 16, 23, 28, 32]
7: [7, 17, 71, 117, 171]
8: [8, 18, 24, 29, 36]
9: [9, 19, 33, 91, 119]
</pre>


=={{header|C++}}==
=={{header|C++}}==
Retrieved from "https://rosettacode.org/wiki/Digital_root/Multiplicative_digital_root"