evenodd

/Even Odd according to position/


#include <stdio.h>
#include <stdlib.h>

struct node
{
    int info;
    struct node *next;
} *start = NULL;
void create(int n)
{
    if (n <= 0)
        printf("U can't able to store LL");
    else
    {
        struct node *ptr;
        ptr = (struct node *)malloc(sizeof(struct node));
        printf("Enter data: ");
        scanf("%d", &ptr->info);
        ptr->next = NULL;
        start = ptr;
        int i;
        for (i = 1; i < n; i++)
        {
            ptr->next = (struct node *)malloc(sizeof(struct node));
            ptr = ptr->next;
            printf("Enter data: ");
            scanf("%d", &ptr->info);
            ptr->next = NULL;
        }
        printf("\n");
    }
}
void EvenOddAccordingToPostion()
{
    struct node *odd1, *odd2, *even1, *even2;
    odd1 = start;
    even1 = start->next;
    if (odd1 == NULL || even1 == NULL || even1->next == NULL)
    {
        return;
    }
    else
    {
        odd2 = even1->next;
        even2 = odd2->next;
        while (even2 != NULL)
        {
            even1->next = even2;
            odd2->next = even1;
            odd1->next = odd2;
            odd1 = odd1->next;
            even1 = even2;
            if (even2->next == NULL)
                return;
            else
                odd2 = even2->next;
            even2 = odd2->next;
        }
        if (odd2->next == NULL)
        {
            odd2->next = odd1->next;
            even1->next = NULL;
            odd1->next = odd2;
        }
    }
}
void display()
{
    struct node *p;
    p = start;
    while (p != NULL)
    {
        printf("%d   ", p->info);
        p = p->next;
    }
    printf("\n\n");
}
int main()
{
    int n;
    printf("Enter total number of element ");
    scanf("%d", &n);
    create(n);
    EvenOddAccordingToPostion();
    display();
    return 0;
}