numbers_divisible_by_all_its_digits.c

/*

    numbers_divisible_by_all_its_digits.c       by Dragan Milicev

    Find all positive integers divisible with all of their digits that are non-zero.


    You can find all my C programs at Dragan Milicev's pastebin:

    https://pastebin.com/u/dmilicev

*/

#include <stdio.h>
#include <limits.h>     // for USHRT_MAX = 65535


// extract digits from number into array digits[]
// returns the number of extracted digits
int extract_digits_from_number( int number, int digits[20] )
{
    int i, j, number_of_digits = 0, mem;

    while( number != 0 )
    {
        digits[number_of_digits++] = number % 10;   // fill array digits[]
        number = number / 10;
    }

    // reverse first number_of_digits elements of array digits[]
    for ( i=0, j=number_of_digits-1; i<number_of_digits/2; i++, j-- )
    {
        mem = digits[i];
        digits[i] = digits[j];
        digits[j] = mem;
    }

    return( number_of_digits );

} // extract_digits_from_number


int main(void)
{
    int number = 12345;     // our number
    int digits[20];         // array to store digits of number
    int number_of_digits=0; // number of digits in number
    int i, j, sum, counter=0;

    printf("\n number = %d and it's digits are: \n", number );

    number_of_digits = extract_digits_from_number( number, digits );

    for ( i=0; i<number_of_digits; i++)
        printf("\n %d \n", digits[i] );

    printf("\n number_of_digits = %d \n\n", number_of_digits );

    system("PAUSE");

    for ( i=1; i<USHRT_MAX; i++)
    {
        number_of_digits = extract_digits_from_number( i, digits );
        sum = 0;

        for ( j=0; j<number_of_digits; j++)
        {
            if ( digits[j] != 0 )
            {
                sum = sum + i%digits[j];
            }
        }

        if ( sum == 0 )
        {
            counter++;
            printf("\n %4d. \t %5d \n", counter, i );
        }
    }

    printf("\n\n From 1 to %d, there are %d numbers \n\n divisible with all of their digits that are non-zero. \n\n",
            USHRT_MAX, counter );


    return 0;

} // main()