reverse linked list in c

1class LinkedList { 
2  
3    static Node head; 
4  
5    static class Node { 
6  
7        int data; 
8        Node next; 
9  
10        Node(int d) 
11        { 
12            data = d; 
13            next = null; 
14        } 
15    } 
16  
17    /* Function to reverse the linked list */
18    Node reverse(Node node) 
19    { 
20        Node prev = null; 
21        Node current = node; 
22        Node next = null; 
23        while (current != null) { 
24            next = current.next; 
25            current.next = prev; 
26            prev = current; 
27            current = next; 
28        } 
29        node = prev; 
30        return node; 
31    } 
32  
33    // prints content of double linked list 
34    void printList(Node node) 
35    { 
36        while (node != null) { 
37            System.out.print(node.data + " "); 
38            node = node.next; 
39        } 
40    } 
41  
42    public static void main(String[] args) 
43    { 
44        LinkedList list = new LinkedList(); 
45        list.head = new Node(85); 
46        list.head.next = new Node(15); 
47        list.head.next.next = new Node(4); 
48        list.head.next.next.next = new Node(20); 
49  
50        System.out.println("Given Linked list"); 
51        list.printList(head); 
52        head = list.reverse(head); 
53        System.out.println(""); 
54        System.out.println("Reversed linked list "); 
55        list.printList(head); 
56    } 
57} 

1/**
2 * C program to reverse a Singly Linked List
3 */
4
5#include <stdio.h>
6#include <stdlib.h>
7
8
9/* Structure of a node */
10struct node {
11    int data; //Data part
12    struct node *next; //Address part
13}*head;
14
15
16/* Functions used in the program */
17void createList(int n);
18void reverseList();
19void displayList();
20
21
22int main()
23{
24    int n, choice;
25
26    /*
27     * Create a singly linked list of n nodes
28     */
29    printf("Enter the total number of nodes: ");
30    scanf("%d", &n);
31    createList(n);
32
33    printf("\nData in the list \n");
34    displayList();
35
36    /*
37     * Reverse the list
38     */
39    printf("\nPress 1 to reverse the order of singly linked list\n");
40    scanf("%d", &choice);
41    if(choice == 1)
42    {
43        reverseList();
44    }
45
46    printf("\nData in the list\n");
47    displayList();
48
49    return 0;
50}
51
52
53/*
54 * Create a list of n nodes
55 */
56void createList(int n)
57{
58    struct node *newNode, *temp;
59    int data, i;
60
61    if(n <= 0)
62    {
63        printf("List size must be greater than zero.\n");
64        return;
65    }
66
67    head = (struct node *)malloc(sizeof(struct node));
68
69    /*
70     * If unable to allocate memory for head node
71     */
72    if(head == NULL)
73    {
74        printf("Unable to allocate memory.");
75    }
76    else
77    {
78        /*
79         * Read data of node from the user
80         */
81        printf("Enter the data of node 1: ");
82        scanf("%d", &data);
83
84        head->data = data; // Link the data field with data
85        head->next = NULL; // Link the address field to NULL
86
87        temp = head;
88
89        /*
90         * Create n nodes and adds to linked list
91         */
92        for(i=2; i<=n; i++)
93        {
94            newNode = (struct node *)malloc(sizeof(struct node));
95
96            /* If memory is not allocated for newNode */
97            if(newNode == NULL)
98            {
99                printf("Unable to allocate memory.");
100                break;
101            }
102            else
103            {
104                printf("Enter the data of node %d: ", i);
105                scanf("%d", &data);
106
107                newNode->data = data; // Link the data field of newNode with data
108                newNode->next = NULL; // Link the address field of newNode with NULL
109
110                temp->next = newNode; // Link previous node i.e. temp to the newNode
111                temp = temp->next;
112            }
113        }
114
115        printf("SINGLY LINKED LIST CREATED SUCCESSFULLY\n");
116    }
117}
118
119
120/*
121 * Reverse the order of nodes of a singly linked list
122 */
123void reverseList()
124{
125    struct node *prevNode, *curNode;
126
127    if(head != NULL)
128    {
129        prevNode = head;
130        curNode = head->next;
131        head = head->next;
132
133        prevNode->next = NULL; // Make first node as last node
134
135        while(head != NULL)
136        {
137            head = head->next;
138            curNode->next = prevNode;
139
140            prevNode = curNode;
141            curNode = head;
142        }
143
144        head = prevNode; // Make last node as head
145
146        printf("SUCCESSFULLY REVERSED LIST\n");
147    }
148}
149
150
151/*
152 * Display entire list
153 */
154void displayList()
155{
156    struct node *temp;
157
158    /*
159     * If the list is empty i.e. head = NULL
160     */
161    if(head == NULL)
162    {
163        printf("List is empty.");
164    }
165    else
166    {
167        temp = head;
168        while(temp != NULL)
169        {
170            printf("Data = %d\n", temp->data); // Print the data of current node
171            temp = temp->next;                 // Move to next node
172        }
173    }
174}

1class recursion { 
2	static Node head; // head of list 
3	static class Node { 
4		int data; 
5		Node next; 
6		Node(int d) 
7		{   data = d; 
8			next = null; 	} } 
9	static Node reverse(Node head) 
10	{ 
11		if (head == null || head.next == null) 
12			return head; 
13		/* reverse the rest list and put the first element 
14        at the end */
15		Node rest = reverse(head.next); 
16		head.next.next = head; 
17		/* tricky step -- see the diagram */
18    	head.next = null; 
19		/* fix the head pointer */
20		return rest; 
21	}  /* Function to print linked list */
22	static void print() 
23	{ 
24		Node temp = head; 
25		while (temp != null) { 
26			System.out.print(temp.data + " "); 
27			temp = temp.next; 
28		} 
29		System.out.println(); 
30	} 
31	static void push(int data) 
32	{ 
33		Node temp = new Node(data); 
34		temp.next = head; 
35		head = temp; 
36	} /* Driver program to test above function*/
37public static void main(String args[]) 
38{ 
39	/* Start with the empty list */
40	push(20); 
41	push(4); 
42	push(15); 
43	push(85); 
44	System.out.println("Given linked list"); 
45	print(); 
46	head = reverse(head); 
47	System.out.println("Reversed Linked list"); 
48	print(); 
49} } // This code is contributed by Prakhar Agarwal 

1	    /* Before changing next pointer of current node,
2        store the next node */
3        next = curr -> next
4        /*  Change next pointer of current node */
5        /* Actual reversing */
6        curr -> next = prev
7        /*  Move prev and curr one step ahead */
8        prev = curr
9        curr = next
10

1#include <stdio.h>
2#include <stdlib.h>
3
4struct node 
5{
6    int num;                    //Data of the node
7    struct node *nextptr;       //Address of the node
8}*stnode;
9
10void createNodeList(int n);     //function to create the list
11void reverseDispList();         //function to convert the list in reverse
12void displayList();             //function to display the list
13
14int main()
15{
16    int n;
17		printf("\n\n Linked List : Create a singly linked list and print it in reverse order :\n");
18		printf("------------------------------------------------------------------------------\n");
19		
20    printf(" Input the number of nodes : ");
21    scanf("%d", &n);
22    createNodeList(n);
23    printf("\n Data entered in the list are : \n");		
24    displayList();
25    reverseDispList();
26    printf("\n The list in reverse are :  \n");
27    displayList();
28    return 0;
29}
30
31void createNodeList(int n)
32{
33    struct node *fnNode, *tmp;
34    int num, i;
35    stnode = (struct node *)malloc(sizeof(struct node));
36    if(stnode == NULL) //check whether the stnode is NULL and if so no memory allocation
37    {
38        printf(" Memory can not be allocated.");
39    }
40    else
41    {
42// reads data for the node through keyboard
43        printf(" Input data for node 1 : ");
44        scanf("%d", &num);
45        stnode-> num = num;      
46        stnode-> nextptr = NULL; //Links the address field to NULL
47        tmp = stnode;
48//Creates n nodes and adds to linked list
49        for(i=2; i<=n; i++)
50        {
51            fnNode = (struct node *)malloc(sizeof(struct node));
52            if(fnNode == NULL) //check whether the fnnode is NULL and if so no memory allocation
53            {
54                printf(" Memory can not be allocated.");
55                break;
56            }
57            else
58            {
59                printf(" Input data for node %d : ", i);
60                scanf(" %d", &num);
61                fnNode->num = num;      // links the num field of fnNode with num
62                fnNode->nextptr = NULL; // links the address field of fnNode with NULL
63                tmp->nextptr = fnNode; // links previous node i.e. tmp to the fnNode
64                tmp = tmp->nextptr;
65            }
66        }
67    }
68}
69
70void reverseDispList()
71{
72    struct node *prevNode, *curNode;
73 
74    if(stnode != NULL)
75    {
76        prevNode = stnode;
77        curNode = stnode->nextptr;
78        stnode = stnode->nextptr;
79 
80        prevNode->nextptr = NULL; //convert the first node as last
81 
82        while(stnode != NULL)
83        {
84            stnode = stnode->nextptr;
85            curNode->nextptr = prevNode;
86 
87            prevNode = curNode;
88            curNode = stnode;
89        }
90        stnode = prevNode; //convert the last node as head
91    }
92}
93
94void displayList()
95{
96    struct node *tmp;
97    if(stnode == NULL)
98    {
99        printf(" No data found in the list.");
100    }
101    else
102    {
103        tmp = stnode;
104        while(tmp != NULL)
105        {
106            printf(" Data = %d\n", tmp->num);   // prints the data of current node
107            tmp = tmp->nextptr;                 // advances the position of current node
108        }
109    }
110}
111 
112

1#include <stdio.h>
2struct Node {
3   int data;
4   struct Node* next;
5   Node(int data){
6      this->data = data;
7      next = NULL;
8   }
9};
10struct LinkedList {
11   Node* head;
12   LinkedList(){
13      head = NULL;
14   }
15   void interReverseLL(){
16      Node* current = head;
17      Node *prev = NULL, *after = NULL;
18      while (current != NULL) {
19         after = current->next;
20         current->next = prev;
21         prev = current;
22         current = after;
23      }
24      head = prev;
25   }
26   void print() {
27      struct Node* temp = head;
28      while (temp != NULL) {
29         printf("%d ", temp-> data);
30         temp = temp->next;
31      }
32      printf("\n");
33   }
34   void push(int data){
35      Node* temp = new Node(data);
36      temp->next = head;
37      head = temp;
38   }
39};
40int main() {
41   LinkedList linkedlist;
42   linkedlist.push(85);
43   linkedlist.push(10);
44   linkedlist.push(65);
45   linkedlist.push(32);
46   linkedlist.push(9);
47   printf("Linked List : \t");
48   linkedlist.print();
49   linkedlist.interReverseLL();
50   printf("Reverse Linked List : \t");
51   linkedlist.print();
52   return 0;
53}
54
55
56Output
57Linked List : 9 32 65 10 85
58Reverse Linked List : 85 10 65 32 9