Algorithm in C - playing with numbers - number with 3 in units place

Question

I came across this question in an interview. Any number with 3 in its units position has at least one multiple containing all ones. For instance, a multiple of 3 is 111, a

Answer 1

The multiple of 23 is 1111111111111111111111

#include 

int
main () {
        unsigned int ones = 1;
        double result, by = 23, dividend = 1;
        while (dividend) {
            result = dividend / by;
                if (result < 1) {
                    dividend = dividend * 10 + 1;
                        ++ones;
                } else {
                    dividend -= by * (int)result;
                }
        }
        while (ones--) {
            printf("1");
        }
        printf("\n");
    return 0;
}