6.9 digit solve by me.

 #include <stdio.h>

int main() {
    int N;
    scanf("%d", &N);
    for (int i = 1; i <= N; i++) {
        int n;
        scanf("%d", &n);
        while (n > 0) {
            int digit = n % 10;
            printf("%d ", digit);
            n = n / 10;
        }
        printf("\n");
    }
    return 0;
}