Code:
#include stdio.h
#include stdlib.h
struct node
{
int num;
struct node *next;
};
void create(struct node **);
void reverse(struct node **, int);
void release(struct node **);
void display(struct node *);
int main()
{
struct node *p = NULL;
int n;
printf("Enter data into the list\n");
create(&p);
printf("Displaying the nodes in the list:\n");
display(p);
printf("Enter the number N to reverse first N node: ");
scanf("%d", &n);
printf("Reversing the list...\n");
if (n > 1)
{
reverse(&p, n - 2);
}
printf("Displaying the reversed list:\n");
display(p);
release(&p);
return 0;
}
void reverse(struct node **head, int n)
{
struct node *p, *q, *r, *rear;
p = q = r = *head;
if (n == 0)
{
q = q->next;
p->next = q->next;
q->next = p;
*head = q;
}
else
{
p = p->next->next;
q = q->next;
r->next = NULL;
rear = r;
q->next = r;
while (n > 0 && p != NULL)
{
r = q;
q = p;
p = p->next;
q->next = r;
n--;
}
*head = q;
rear->next = p;
}
}
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 display(struct node *p)
{
while (p != NULL)
{
printf("%d\t", p->num);
p = p->next;
}
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]: 1
Enter number: 6
Do you wish to continue [1/0]: 1
Enter number: 7
Do you wish to continue [1/0]: 0
Displaying the nodes in the list:
1 2 3 4 5 6 7
Enter the number N to reverse first N node: 4
Reversing the list...
Displaying the reversed list:
4 3 2 1 5 6 7
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