Searching in Doubly Linked List

by Online Tutorials Library July 22, 2022

Searching for a specific node in Doubly Linked List

We just need traverse the list in order to search for a specific element in the list. Perform following operations in order to search a specific operation.

Copy head pointer into a temporary pointer variable ptr.

declare a local variable I and assign it to 0.

Traverse the list until the pointer ptr becomes null. Keep shifting pointer to its next and increasing i by +1.
Compare each element of the list with the item which is to be searched.
If the item matched with any node value then the location of that value I will be returned from the function else NULL is returned.

Algorithm

Step 1: IF HEAD == NULL

&nbspWRITE “UNDERFLOW”
&nbspGOTO STEP 8
[END OF IF]

Step 2: Set PTR = HEAD
Step 3: Set i = 0
Step 4: Repeat step 5 to 7 while PTR != NULL
Step 5: IF PTR → data = item

return i
[END OF IF]

Step 6: i = i + 1
Step 7: PTR = PTR → next
Step 8: Exit

C Function

  #include<stdio.h>  #include<stdlib.h>  void create(int);  void search();  struct node  {  int data;  struct node *next;  struct node *prev;  };  struct node *head;  void main ()  {  int choice,item,loc;  do   {  printf(“n1.Createn2.Searchn3.Exitn4.Enter your choice?”);  scanf(“%d”,&choice);  switch(choice)  {  case 1:  printf(“nEnter the itemn”);  scanf(“%d”,&item);  create(item);  break;   case 2:  search();  case 3:  exit(0);  break;  default:  printf(“nPlease enter valid choicen”);  }    }while(choice != 3);  }  void create(int item)  {        struct node *ptr = (struct node *)malloc(sizeof(struct node));     if(ptr == NULL)     {         printf(“nOVERFLOW”);     }     else     {                 if(head==NULL)     {         ptr->next = NULL;         ptr->prev=NULL;         ptr->data=item;         head=ptr;     }     else      {         ptr->data=item;printf(“nPress 0 to insert more ?n”);         ptr->prev=NULL;         ptr->next = head;         head->prev=ptr;         head=ptr;     }  printf(“nNode Insertedn”);  }       }  void search()  {  struct node *ptr;  int item,i=0,flag;  ptr = head;   if(ptr == NULL)  {  printf(“nEmpty Listn”);  }  else  {   printf(“nEnter item which you want to search?n”);   scanf(“%d”,&item);  while (ptr!=NULL)  {  if(ptr->data == item)  {  printf(“nitem found at location %d “,i+1);  flag=0;  break;  }   else  {  flag=1;  }  i++;  ptr = ptr -> next;  }  if(flag==1)  {  printf(“nItem not foundn”);  }  }    }  

Output

1.Create  2.Search  3.Exit  4.Enter your choice?1    Enter the item  23    Node Inserted    1.Create  2.Search  3.Exit  4.Enter your choice?1    Enter the item  90    Node Inserted    1.Create  2.Search  3.Exit  4.Enter your choice?2    Enter item which you want to search?  90    item found at location 1

Next TopicDoubly Linked List

Searching in Doubly Linked List

Searching for a specific node in Doubly Linked List

Algorithm

C Function

DAA Algorithm

Chutney vs Pickle

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