Permuted multiples: Difference between revisions
Add C
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6 * n = 857142"
</lang>
=={{header|C}}==
<lang c>#include <stdio.h>
#include <stdbool.h>
/* Find the set of digits of N, expressed as a number
where the N'th digit represents the amount of times
that digit occurs. */
int digit_set(int n) {
static const int powers[] = {
1, 10, 100, 1000, 10000, 100000, 1000000, 10000000,
100000000, 1000000000
};
int dset;
for (dset = 0; n; n /= 10)
dset += powers[n % 10];
return dset;
}
/* See if for a given N, [1..6]*N all have the same digits */
bool is_permuted_multiple(int n) {
int dset = digit_set(n);
for (int mult = 2; mult <= 6; mult++)
if (dset != digit_set(n * mult)) return false;
return true;
}
/* Find the first matching number */
int main() {
int n;
for (n = 123; !is_permuted_multiple(n); n++);
for (int mult = 1; mult <= 6; mult++)
printf("%d * n = %d\n", mult, n*mult);
return 0;
}</lang>
{{out}}
<pre>1 * n = 142857
2 * n = 285714
3 * n = 428571
4 * n = 571428
5 * n = 714285
6 * n = 857142</pre>
=={{header|C++}}==
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