Reversing a linked list

c_programs/reverse_a_linked_list.c

@@ -0,0 +1,66 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+//defining each node of a linked list
+typedef struct Node
+{
+    int data;
+    struct Node *next;
+}node;
+
+//inserting a new node at the beginning and updating head of the list
+void insertNode(node **head,int data)
+{
+    node *temp=(node*)malloc(sizeof(node*));
+    temp->data=data;
+    temp->next=*head;
+    *head=temp;
+}
+
+//displays the whole linked list from head to end
+void printList(node *head)
+{
+    while(head!=NULL)
+    {
+        printf("%d ",head->data);
+        head=head->next;
+    }
+    printf("\n");
+    return;
+}
+
+//reverses the linked list by reversing the next pointer of each node
+//three pointers are maintained pointing to the current node and nodes previous and next to the current node
+void reverse(node **head)
+{
+    if(*head==NULL || (*head)->next==NULL)
+        return;
+    node *curr=*head;
+    node *prev=NULL;
+    node *next=NULL;
+    while(curr!=NULL)
+    {
+        next=curr->next;
+        curr->next=prev;
+        prev=curr;
+        curr=next;
+    }
+    *head=prev;
+}
+
+//driver program to test the above functions
+int main()
+{
+    node *head=NULL;
+    insertNode(&head,1);
+    insertNode(&head,2);
+    insertNode(&head,3);
+    insertNode(&head,4);
+    insertNode(&head,5);
+    printf("The original list is:\n");
+    printList(head);
+    reverse(&head);
+    printf("The reversed List is:\n");
+    printList(head);
+    return 0;
+}