Delete a node in linked list without head pointer

Generally, people ask the question to delete a node in linked list without head pointer. It is a tricky question because the general approach to delete the given node is that traverse the linked list till the node which you want to delete. In this article, I will describe that how we can delete a node without using the head pointer.

You can also see, Delete a Linked List node using the head pointer

There is no practical solution to delete a node directly by given pointer, we need to do some trick. We need to copy the data from the next node to the current node by given pointer to be deleted and delete the next node.

//Get the Address of the next node
NodePointer temp = Node->pNextNode; 


//Get the data of next node
Node->iData = temp->iData; 


//Get the Address of next to next node
Node->pNextNode = temp->pNextNode; 
 
  
//Delete the next node
free(temp);

 

Note: You can not use this technique to delete the last node.

Program to delete a node in linked list without head pointer

 

#include<stdio.h>
#include<stdlib.h>
 
 
// Creating Node
struct Node 
{
  /*Data field*/
  int iData;
  /*Node Pointer*/
  struct Node *pNextNode;
};
 
 
// Define the new type Node type and Node pointer
typedef  struct Node  NodeType, * NodePointer;



/* Paas the reference of the head pointer of a list and 
   an integer data. This function use to add the node at the beginning*/
int InsertNodeAtBeginning(NodePointer * pHead, int iUserData) 
{
	int iRetValue = -1;
	
	// Call malloc to allocate memory in heap for the new node
	NodePointer pNewNode = malloc(sizeof(NodeType));
	
	if( pNewNode != NULL) //Check allocated memory
	{
		pNewNode->iData = iUserData; //put the desire Data
		
		pNewNode->pNextNode  = *pHead; //Give the Address of first Node
		
		*pHead = pNewNode; // Assign the Address of New Node to Head
		
		iRetValue = 0; // Update the return value
		
	}
	return iRetValue;
}
 
 
//Delete Any node of the linked list
void DeleteNode(NodePointer Node)    
{ 
   NodePointer temp = Node->pNextNode; 
   
   Node->iData = temp->iData; 
   
   Node->pNextNode = temp->pNextNode; 
   
   free(temp); 
} 
  

/* Paas the reference of the head pointer of a list and 
   an integer data. This function use to add the node at the End*/
int InsertNodeAtEnd(NodePointer * pHead, int iUserData) 
{
	int iRetValue = -1;
	
	NodePointer pLastNode = NULL;
	NodePointer pNewNode = NULL;
	
	//Give the Address of first Node
	pLastNode  = *pHead;
	
	// Call malloc to allocate memory in heap for the new node
	pNewNode = malloc(sizeof(NodeType));
	
	if( pNewNode != NULL) //Check allocated memory
	{
		pNewNode->iData = iUserData; //put the desire Data
		
		pNewNode->pNextNode  = NULL; //Give the Address of first Node
		
		iRetValue = 0; // Update the return value
		
	}
	// If there is no node in beginning
	if(pLastNode == NULL)
	{
		*pHead = pNewNode;
	}
	else 
	{
		// Find the address of last node
		while( pLastNode ->pNextNode != NULL)
		{
			pLastNode  = pLastNode ->pNextNode;
		}
	
	   // Assign last node address
	    pLastNode ->pNextNode = pNewNode;

	}
	
	return iRetValue;
}

 
// This function use to prints the data of the list from the begning
//to the given list.
 
void PrintTheList(NodePointer pNode)
{
  
  printf("Linked List is = ");
  while (pNode != NULL)
  {
     printf("%d ",pNode->iData);
     pNode = pNode->pNextNode;
  }
  	
}


//Create a linked list of certain number of nodes
int CreateLinkedList(NodePointer *pHead, int iNumberofNode)
{
	int iData = 0;
	int iRetValue = -1;
	int iCount = 0;
	
	for(iCount =0; iCount < iNumberofNode; iCount++)
	{
		/*Enter desire data*/
		printf("\nEnter the Data = ");
		scanf("%d",&iData);
		
		if((*pHead) == NULL)
		{
			//Create First Node
	           iRetValue = InsertNodeAtBeginning(pHead,iData);
		}
		else
		{
			//Add the Node at the End
			iRetValue = InsertNodeAtEnd(pHead,iData);
			
		}
	}
	
	return iRetValue;
}


/* Driver program to test above functions*/
int main(void)
{
   int iRetValue = -1;
   int iNumberNode =0;
	
   /*Start with the empty list */
   NodePointer head = NULL;
   
   
   printf("\nEnter the number of nodes = ");
   scanf("%d",&iNumberNode);
   
   //Create the linked list
   iRetValue = CreateLinkedList(&head,iNumberNode);
   if(iRetValue == -1)
   {
   	 printf("List is empty !\n");
   	 return 0;
   }
    
   printf("\nLinked list before deleting the node\n");
   //Print the list
   PrintTheList(head);
   
   //delete the head
   DeleteNode(head);
   
   printf("\nLinked list after deleting the node\n");

   //Print the list
   PrintTheList(head);
   
  return 0;
}