Assignment 8 Question 1

#include <stdio.h>

#include <stdlib.h>



struct DoublyLinkedList{

int data;

struct DoublyLinkedList *prev;

struct DoublyLinkedList *next;

};


void removeNode (
struct DoublyLinkedList **headptr,
struct DoublyLinkedList **tailptr,
struct DoublyLinkedList *ptr)
{
if ( ptr == *headptr ){
*headptr = ptr->next;
(*headptr)->prev = NULL;
}else{
if ( ptr == *tailptr ) {
*tailptr = ptr->prev;
(*tailptr)->next=NULL;
}else{
ptr->prev->next = ptr->next;
ptr->next->prev = ptr->prev;
}
}
free ( ptr );
ptr = NULL;
return;
}

void removeData (
struct DoublyLinkedList **headptr,
struct DoublyLinkedList **tailptr,
int n)
{
struct DoublyLinkedList *curr;
curr = *headptr;

while ( curr != NULL && curr->data != n ){
curr = curr->next;
}
if ( curr != NULL ){
removeNode(headptr, tailptr, curr);
}
return;
}

struct DoublyLinkedList *createNode(int n)

{

struct DoublyLinkedList *newNodeptr;

newNodeptr = (struct DoublyLinkedList*)

malloc (sizeof(struct DoublyLinkedList));

newNodeptr->data = n;

newNodeptr->prev = NULL;

newNodeptr->next = NULL;

return newNodeptr;

}



/*

 --------------------------------

 add a node at the end of a doubly linked list.

 Tailptr is the address of the pointer to the end of the current list.

 After adding the node, tail points to the new node inserted.

 --------------------------------

*/

void appendNode ( struct DoublyLinkedList **tailptr, int n )

{

struct DoublyLinkedList *newNode;

newNode = createNode ( n );

newNode->prev=*tailptr;



(*tailptr)->next = newNode;



*tailptr=newNode;

}



void initializeList (

struct DoublyLinkedList **headptr,

struct DoublyLinkedList **tailptr,

int n)

{

struct DoublyLinkedList *newNode;

newNode=createNode(n);

*headptr=newNode;

*tailptr=newNode;

return;

}



void printList(

struct DoublyLinkedList *head,

struct DoublyLinkedList *tail)

{

struct DoublyLinkedList *curr=head;



while ( curr != NULL ){

                if(curr->next!=NULL)

printf("%d,",curr->data);

                else printf("%d",curr->data);

curr = curr->next;

}



return;

}



/*

 --------------------------------

 remove the node that ptr points to.

 After removing the first node, we should reset head.

 After removing the last node, we should reset tail.

 --------------------------------

*/

int main()

{

int n;

int i=0;

int m;

struct DoublyLinkedList *head, *tail;



scanf("%d",&n);



if ( n <= 0 ){

return 0;

}



scanf("%d",&m);

initializeList(&head,&tail,m);





for(i=1;i<n;i++){ /* read the remaining elements */

scanf("%d",&m);

appendNode(&tail,m);

}

  scanf("%d",&n);

removeData ( &head, &tail, n );

printList(head,tail);

return 0;

}