int main()
{
    int arr[]= {11, 13, 21, 3};
    int n = sizeof(arr)/sizeof(arr[0]);
    nextGreater(arr, n);
    //  getchar();
    return 0;
}
main()
{
    char num[100] = "13625", smaller[100], greater[100];
    printf("\nNumber: %s", num);
    strcpy(smaller, num);
    nextSmaller(smaller);
    printf("\nSmaller: %s", smaller);
    strcpy(greater, num);
    nextGreater(greater);
    printf("\nGreater: %s", greater);
}