Do you want to share? =D

I've got a book called 'C Programming: A Modern Approach', it's the text book students of C Programming use for refering. Since weeks back I've been reading this book to recall my knowledge in C and trying to catch some more information & experience. The main point now is 'Arrays section'. I've never learn arrays in C. I was only dealing with arrays in Java and they really look much nicer in Java than in C lols..
Anyway, there is a problem I was hitting on since couple of days and til now there is no answer.

let me show it to you:

/* Checks number for repeated digits */

#include<stdio.h>

#define TRUE 1;
#define FALSE 0;

typedef int Bool;

main()
{
    Bool digit_seen[10]={0};
    int digit;
    long int n;

    printf("Enter a number: ");
    scanf("%d", &n);

    while (n > 0)
    {
        digit=n%10;
        if (digit_seen[digit])
            break;
        digit_seen[digit] = TRUE;
        n /= 10;
    }

    if (n > 0)
        printf("Repeated digit\n\n");
    else
        printf("No repeated digit\n\n");

    return 0;
}

To be honest I spent a long period to understand that code. I didn't start solving the problem until I got the idea about it =D
anyway, I want to share the question with you guys, I think it's fun for all of us to think and try to come with a solution or an idea about how the answer code will be.

Here's the exercise:
Modify the repdigit.c program (The above program) so that it shows which digits (if any) were repeated:
Enter a number: 93977
Repeated digit(s): 7 9

didn't figure it out yet but I'm still trying. Here's what I went through so far:
#include<stdio.h>

#define TRUE 1;
#define FALSE 0;

typedef int Bool;

main()
{
    Bool digit_seen[10]={0};
    Bool repeated_digit[10];
    int digit;
    long int n;

    printf("Enter a number: ");
    scanf("%d", &n);

    while (n > 0)
    {
        digit=n%10;
        if (digit_seen[digit])
            {repeated_digit[digit]=digit;
            }

        digit_seen[digit] = TRUE;
        n /= 10;
    }

    if (repeated_digit[digit])
        {printf("Repeated digit\n\n");
        printf("%d", repeated_digit[digit]);}
    else
        {printf("No repeated digit\n\n");
        printf("%d", n);}
    return 0;
}
it's a wrong answer and I've been changing it from the beginning to now =D

enjoy it =)

peace~