reverse a singly linked list in c

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}

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