Code:
#include stdio.h
#include stdlib.h
struct node
{
int num;
struct node *next;
};
void create(struct node **);
void nthnode(struct node *, int);
void release(struct node **);
int main()
{
struct node *p = NULL;
int n;
printf("Enter data into the list\n");
create(&p);
printf("Enter the value n to find nth position from the last node: ");
scanf("%d", &n);
nthnode(p, n);
release (&p);
return 0;
}
void nthnode(struct node *head, int n)
{
struct node *p, *q;
int i;
q = p = head;
for (i = 0; i < n && q != NULL; i++)
{
q = q->next;
}
if (i < n)
{
printf("Entered n = %d is larger than the number of elements = %d in list. Please try again.\n", n, i);
}
else
{
while (q->next != NULL)
{
q = q->next;
p = p->next;
}
printf("%d is %d nodes from the last node.\n", p->num, n);
}
}
void create(struct node **head)
{
int c, ch;
struct node *temp, *rear;
do
{
printf("Enter number: ");
scanf("%d", &c);
temp = (struct node *)malloc(sizeof(struct node));
temp->num = c;
temp->next = NULL;
if (*head == NULL)
{
*head = temp;
}
else
{
rear->next = temp;
}
rear = temp;
printf("Do you wish to continue [1/0]: ");
scanf("%d", &ch);
} while (ch != 0);
printf("\n");
}
void release(struct node **head)
{
struct node *temp = *head;
*head = (*head)->next;
while ((*head) != NULL)
{
free(temp);
temp = *head;
(*head) = (*head)->next;
}
}
Output:
Enter data into the list
Enter number: 1
Do you wish to continue [1/0]: 1
Enter number: 2
Do you wish to continue [1/0]: 1
Enter number: 3
Do you wish to continue [1/0]: 1
Enter number: 4
Do you wish to continue [1/0]: 1
Enter number: 5
Do you wish to continue [1/0]: 0
Enter the value n to find nth position from the last node: 2
3 is 2 nodes from the last node.
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