Program to reverse the linked list.

#include<stdio.h>
#include<stdlib.h>
struct node
{
int data;
struct node *next;
};
main()
{
struct node *start=NULL;
int n;
void create(struct node **, int);
void show(struct node *);
void reverse(struct node **);
printf("Enter the number of elements you want in your linked list :");
scanf("%d",&n);
create(&start,n);
show(start);
reverse(&start);
show(start);
getch();  
}

void create(struct node **q,int n)
{
int i;
struct node *lst;
struct node *p;
lst=NULL;
for(i=1;i<=n;i++)
{
 p=(struct node *)malloc(sizeof(struct node));
 printf("Enter the %d element :",i);
 scanf("%d",&(p->data));
 p->next=NULL;
 if(*q==NULL)
    *q=p;
 else
   lst->next=p;
  lst=p;
}
}

void show(struct node *start)
{
printf("Entered linked list is :\n");
while(start!=NULL)
{
printf(" %d\n",start->data);
start=start->next;
}
}

void reverse(struct node **start)
{
     struct node *new_start=NULL,*ptr,*temp;
     ptr=*start;
     while(ptr!=NULL)
     {
      if(new_start==NULL)
       {
         new_start=ptr;
         ptr=ptr->next;
         new_start->next=NULL;
       }
       else
       {
           temp=ptr;
           ptr=ptr->next;
           temp->next=new_start;
           new_start=temp;
       }
     }
     *start=new_start;  
}

Posted in: Data Structure,Linked List(Self Referential structure)

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