/*The program creates two linked lists:
one of even numbers and one of odd numbers
The program calculates sum, min, and max for each list*/
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <malloc.h>

typedef struct element
{
    int data;
    struct element *ptr_next;
} element;

/* 3 alternative solutions for even odd lists */
int even_odd(element **, element **);
int even_odd1(element **, element **);
int even_odd2(element **, element **);
int sum_min_max(element *lst, int *min, int *max);
void print_list (element *lst);
void free_list (element *lst);
void insert_new_element_to_list(element **list, int x);

void main ()
{
    element *even_num_list, *odd_num_list;
    int min_even, max_even, sum_even, min_odd, max_odd, sum_odd,

    num = even_odd (&even_num_list, &odd_num_list);
    sum_even = sum_min_max (even_num_list, &min_even, &max_even);
    sum_odd = sum_min_max (odd_num_list, &min_odd, &max_odd);
    printf ("%d numbers:\n", num);
    printf ("even_numbers: ");
    print_list (even_num_list);
    if (even_num_list)
        printf ("\n(sum=%d min=%d max=%d)\n", sum_even, min_even, max_even);
    else
        printf ("\n(sum=%d)\n", sum_even);
    printf ("odd_numbers: ");
    print_list (odd_num_list);
    if (odd_num_list)
        printf ("\n(sum=%d min=%d max=%d)\n", sum_odd, min_odd, max_odd);
    else
        printf ("\n(sum=%d)\n", sum_odd);
    free_list (even_num_list);
    free_list (odd_num_list);

    /* Alternative solution for the even odd lists without a dummy element */
    num = even_odd1(&even_num_list, &odd_num_list);
    printf("even_numbers: ");
    print_list(even_num_list);
    printf("\nodd_numbers: ");
    print_list(odd_num_list);
    free_list(even_num_list);
    free_list(odd_num_list);

    /* Alternative solution for the even odd lists without a dummy element
       but the order of the elements of the list will be opposite than entered */
    num = even_odd2(&even_num_list, &odd_num_list);
    printf("even_numbers: ");
    print_list(even_num_list);
    printf("\nodd_numbers: ");
    print_list(odd_num_list);
    free_list(even_num_list);
    free_list(odd_num_list);

    getchar();
}

/* adding the new number to the END of the relevant list odd/even */
int even_odd(element **even_list, element **odd_list)
{
    element *even_ptr, *odd_ptr; /* will point to the last element that was added to each list */
    int count = 0, x;

    /* creating a dummy first element to avoid a special treatment for the first item in each list */
    *even_list = (element *)malloc(sizeof(element));
    *odd_list = (element *)malloc(sizeof(element));
    even_ptr = *even_list;
    odd_ptr = *odd_list;
    printf("Enter numbers: ");
    scanf("%d", &x);
    while (x != -1)
    {
        if (x % 2 == 0)
        {
            even_ptr->ptr_next = (element *)malloc(sizeof(element));
            even_ptr = even_ptr->ptr_next;
            even_ptr->data = x;
        }
        else
        {
            odd_ptr->ptr_next = (element *)malloc(sizeof(element));
            odd_ptr = odd_ptr->ptr_next;
            odd_ptr->data = x;
        }
        count++;
        scanf("%d", &x);
    }
    even_ptr->ptr_next = odd_ptr->ptr_next = NULL; /* adding NULL at the end of each list */

    /* removing dummy element in each list and free it,
    each list will point to the first real element in the list */
    even_ptr = *even_list;
    *even_list = (*even_list)->ptr_next;
    free(even_ptr);
    odd_ptr = *odd_list;
    *odd_list = (*odd_list)->ptr_next;
    free(odd_ptr);
    return count;
}

/* adding the new number to the END of the relevant list odd/even */
int even_odd1(element **even_list, element **odd_list)
{
    element *even_ptr, *odd_ptr; /* will point to the last element that was added
                                 a special treatment for the first element that we add is required */
    int count = 0, x;

    *even_list = *odd_list = NULL; /* at the beginning both lists are empty */
    even_ptr = *even_list;
    odd_ptr = *odd_list;
    printf("\nEnter numbers: ");
    scanf("%d", &x);
    while (x != -1)
    {
        if (x % 2 == 0)
        {
            if (*even_list)
            {
                /* not first element in the list */
                even_ptr->ptr_next = (element *)malloc(sizeof(element));
                even_ptr = even_ptr->ptr_next;
                even_ptr->data = x;
            }
            else
            {
                /* first element in the list */
                even_ptr = (element *)malloc(sizeof(element));
                even_ptr->data = x;
                *even_list = even_ptr; /* the even list will point on the first element */
            }
        }
        else
        {
            if (*odd_list)
            {
                /* not first element in the list */
                odd_ptr->ptr_next = (element *)malloc(sizeof(element));
                odd_ptr = odd_ptr->ptr_next;
                odd_ptr->data = x;
            }
            else
            {
                /* first element in the list */
                odd_ptr = (element *)malloc(sizeof(element));
                odd_ptr->data = x;
                *odd_list = odd_ptr; /* the odd list will point on the first element */
            }
        }
        count++;
        scanf("%d", &x);
    }

    /* pointing the end of the lists to NULL*/
    if (even_ptr)
        even_ptr->ptr_next = NULL;
    if (odd_ptr)
        odd_ptr->ptr_next = NULL;

    getchar();
    return count;
}


void insert_new_element_to_list(element **list, int x)
{
    element *tmp_ptr;
    if (*list)
    {
        /* not first element in the list */
        tmp_ptr = *list; /* will save a pinter to the first element */
        *list = (element *)malloc(sizeof(element)); /* the head of the list will point to the new element */
        (*list)->ptr_next = tmp_ptr; /* the new first element will point on the old first element */
        (*list)->data = x;
    }
    else
    {
        /* first element in the list */
        *list = (element *)malloc(sizeof(element));
        (*list)->data = x;
        (*list)->ptr_next = NULL;
    }
    return;
}


/* adding the new number to the BEGINNING of the relevant list odd/even */
int even_odd2 (element **even_list, element **odd_list)
{
    int count = 0, x;

    *even_list = *odd_list = NULL; /* at the beginning both lists are empty */

    printf ("\nEnter numbers: ");
    scanf ("%d", &x);
    while (x != -1)
    {
        if (x % 2 == 0)
        {
            insert_new_element_to_list(even_list, x);
        }
        else
        {
            insert_new_element_to_list(odd_list, x);
        }
        count++;
        scanf ("%d", &x);
    }

    getchar();
    return count;
}

int sum_min_max (element *lst, int *min, int *max)
{
    int sum = 0;
    if (lst)
        *min = *max = lst->data;
    while (lst)
    {
        if (lst->data < *min)
            *min = lst->data;
        else
            if (lst->data > *max)
                *max = lst->data;
        sum += lst->data;
        lst = lst->ptr_next;
    }
    return sum;
}


void print_list (element *lst)
{
    while (lst)
    {
        printf ("%d ", lst->data);
        lst = lst->ptr_next;
    }
}

void free_list (element *lst)
{
    element *temp;

    while (lst)
    {
        temp = lst;
        lst = lst->ptr_next;
        free (temp);
    }
}