Reverse linked list C

reverse.txt

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Write a program (WAP) in C to reverse a linked list iterative and recursive. PPL Practical Question.

``````#include <stdio.h>

struct Node
{
int data;
struct Node* next;
};

/* Function to reverse the linked list */
static void reverse(struct Node** head_ref)
{
struct Node* prev   = NULL;
struct Node* current = *head_ref;
struct Node* next = NULL;
while (current != NULL)
{
// Store next
next  = current->next;

// Reverse current node's pointer
current->next = prev;

// Move pointers one position ahead.
prev = current;
current = next;
}
*head_ref = prev;
}

/* Function to push a node */
void push(struct Node** head_ref, int new_data)
{
struct Node* new_node =
(struct Node*) malloc(sizeof(struct Node));
new_node->data  = new_data;
new_node->next = (*head_ref);
(*head_ref)    = new_node;
}

/* Function to print linked list */
void printList(struct Node *head)
{
struct Node *temp = head;
while(temp != NULL)
{
printf("%d  ", temp->data);
temp = temp->next;
}
}

void recursiveReverse(struct Node** head_ref)
{
struct Node* first;
struct Node* rest;

/* empty list */
if (*head_ref == NULL)
return;

/* suppose first = {1, 2, 3}, rest = {2, 3} */
first = *head_ref;
rest  = first->next;

/* List has only one node */
if (rest == NULL)
return;

/* reverse the rest list and put the first element at the end */
recursiveReverse(&rest);
first->next->next  = first;

/* tricky step -- see the diagram */
first->next  = NULL;

/* fix the head pointer */
*head_ref = rest;
}

/* Driver program to test above function*/
int main()
{
/* Start with the empty list */
struct Node* head = NULL;

push(&head, 20);
push(&head, 4);
push(&head, 15);
push(&head, 85);

printf("Given linked list\n");
printList(head);
recursiveReverse(&head);
printf("\nReversed Linked list \n");
printList(head);
getchar();
}

``````

Related searches: C program to reverse a linked list, recursive reverse linked list, iterative reverse linked list.

Last Updated: July 17, 2022