строки_2

#include <stdio.h>
#include <string.h>
#include <ctype.h>

char * order_string(char * s)
{
    char * head = s, * tail = s + strlen(s) - 1;
    while (head < tail)
    {
        if ( ! isdigit(*head) )
            ++head;
        else {
            char tmp = *head;
            memmove(head, head + 1, tail - head);
            *tail-- = tmp;
        }
    }
    return s;
}

int main()
{
    char s_in[] = "ad2e57b6";
    printf("IN string:  %s\n", s_in);
    printf("OUT string: %s\n", order_string(s_in));
    return 0;
}