1 / 26

UNIT 1

Data Structures Using C Linked List By Rohit Khokher Department of Computer Science, Vidya College of Engineering, Meerut, India. UNIT 1. LINKED LIST. START. x. A Linked List is a linear collection of data elements called nodes, where the linear order is given by means of pointers.

pello
Download Presentation

UNIT 1

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Data Structures Using C Linked List By Rohit Khokher Department of Computer Science, Vidya College of Engineering, Meerut, India UNIT 1

  2. LINKED LIST START x • A Linked List is a linear collection of data elements called nodes, where the linear order is given by means of pointers. • The each node is divided into two parts: the first part contain the information of the element, and the second part, called the link field contains the address of t he next node in the list. LINK LIST WITH 4 NODES UNIT 1

  3. The pointer of the last node contains a special value called a null pointer which is any invalid address. • The value of null character is either ’0’ or ‘any negative value’. • The linked list also contains a list pointer variable called start which contains the address of the first node of the link list. • A special case in a list is that has no node such that list is called a null or empty list and it is represented by the null pointer in the start. • Example:- create a link list for marks of five subject 89,75,78,80,74 in ascending order UNIT 1

  4. START 5 89 0 75 3 78 4 80 1 74 2 LINK LIST REPRESENTATION OF THE MARKS UNIT 1

  5. ALGORITHM FOR TRAVERSING A LINKED LIST • Set PTR=START [Initializes pointer PTR] • Repeat steps 3 & 4 while PTR != NULL • Apply process to INFO[PTR] • 4. Set PTR:- LINK[PTR] • [PTR now points to next node] • [End of step 2 loop] • 5. Exit UNIT 1

  6. PTR PTR=LINK[PTR] UNIT 1

  7. ALGORITHM FOR SEARCHING IN A UNSORTED LINKED LIST • SEARCH(INFO,LINK,START,ITEM,LOC) • SET PTR = START • REPEAT STEP 3 WHILE PTR != NULL • IF ITEM = INFO[PTR] then SET LOC = PTR & EXIT ELSE SET PTR= LINK[PTR] [PTR now points to the next node] [END OF IF STRUCTURE] [END OF STEP 2 LOOP] • [SEARCH IS UNSUCESSFUL] SET LOC=NULL • EXIT UNIT 1

  8. ALGORITHM FOR SEARCHING IN SORTED LIST • SRCHSL(INFO,LINK,START,ITEM,LOC) • SET PTR = START • REPEAT STEP 3 WHILE PTR != NULL • IF ITEM < INFO[PTR] then; SET PTR = LINK[PTR] [PTR now points to the next node] ELSE IF ITEM = INFO [PTR] then; SET LOC = PTR & EXIT [search is successful] ELSE SET LOC = NULL & EXIT [item now exceed INFO[PTR]] [END OF IF STRUCTURE] [END OF STEP 2 LOOP] • [SEARCH IS UNSUCESSFUL] SET LOC=NULL • EXIT UNIT 1

  9. OVERFLOW & UNDERFLOW CONDITIONS OVERFLOW will occur with our link list when AVAIL= NULL &there is an insertion UNDERFLOW will occur with our link list when START=NULL & there is a deletion. UNIT 1

  10. INSERTION IN A LINKED LIST • This Can Be Done In Three Ways: • Beginning of the list • Between two nodes • 3. In a sorted list UNIT 1

  11. AT BEGINNING OF THE LINKED LIST START x AVAIL x UNIT 1

  12. START x AVAIL x UNIT 1

  13. ALGORITHM FOR INSERTION AT BEGINNING • INSFIRST(INFO,LINK,START,AVAIL,ITEM) • [OVERFLOW] if AVAIL=NULL, then write OVERFLOW & EXIT • [ Remove first node from AVAIL list] set NEW = AVAIL & AVAIL= LINK[AVAIL] • Set INFO[NEW]=ITEM [copies new data into new node] • Set LINK[NEW]= START [new node points to original first node] • Set START= NEW [changes START so it points to the new node] • exit UNIT 1

  14. INSERT AFTER A GIVEN NODE START x Node A Node B AVAIL x UNIT 1

  15. START Node B Node A x AVAIL Node N x UNIT 1

  16. ALGORITHM FOR INSERTION AT POSITION • INSLOC(INFO,LINK,START,AVAIL,LOC,ITEM) • [OVERFLOW] if AVAIL=NULL, then write OVERFLOW & EXIT • [ Remove first node from AVAIL list] set NEW = AVAIL & AVAIL= LINK[AVAIL] • Set INFO[NEW]=ITEM [copies new data into new node] • If LOC=NULL then [INSERT AS A FIRST NODE] set LINK[NEW]= START & START=NEW else [INSERT node after node with location LOC] set LINK[NEW]=LINK[LOC] & LINK[LOC]=NEW; [END OF IF STRUCTURE] • exit UNIT 1

  17. CREATION OF LINKED LIST #include<stdio.h> #include<conio.h> #include<malloc.h> void main() { struct node { int num; struct node *ptr; }; typedef struct node NODE; NODE *head, *first, *temp; int count=0; int choice=1; first=NULL; while(choice) { head=(NODE *)malloc(sizeof(NODE)); printf("Enter the data item\n"); scanf("%d",&head->num); if(first!=NULL) { temp->ptr=head; temp=head; } UNIT 1

  18. else { first=temp=head; } fflush(stdin); printf("Do you want to continue(type 0 or 1)?\n"); scanf("%d",&choice); } temp->ptr=NULL; temp=first; printf("Status of the linked list is\n"); while(temp!=NULL) { printf("%d",temp->num); count++; temp=temp->ptr; } printf("NULL"); printf("NO of nodes in the list =%d\n",count); getch(); } UNIT 1

  19. Output of the Program Enter the data item 1 Do you want to continue(type 0 or 1)? 1 Enter the data item 2 Do you want to continue(type 0 or 1)? 1 Enter the data item 3 Do you want to continue(type 0 or 1)? 1 Enter the data item 4 Do you want to continue(type 0 or 1)? 0 Status of the linked list is 1234NULLNO of nodes in the list =4 UNIT 1

  20. Insertion in Linked List #include<stdio.h> #include<conio.h> #include<malloc.h> struct node { int info; struct node *next; }; typedef struct node NODE; NODE *start; void createmptylist(NODE *start) { *start=(NODE *)NULL; } void traversinorder(NODE *start) { while(start != (NODE *) NULL) { printf("%d\n",start->info); start=start->next; } } UNIT 1

  21. void insertatbegin(int item) { NODE *ptr; ptr=(NODE *)malloc(sizeof(NODE)); ptr->info=item; if(start==(NODE *)NULL) ptr->next=(NODE *)NULL; else ptr->next=start; start=ptr; } void insert_at_end(int item) { NODE *ptr,*loc; ptr=(NODE *)malloc(sizeof(NODE)); ptr->info=item; ptr->next=(NODE *)NULL; if(start==(NODE*)NULL) start=ptr; UNIT 1

  22. else { loc=start; while(loc->next!=(NODE *)NULL) loc=loc->next; loc->next=ptr; } } void insert_spe(NODE *start,int item) { NODE *ptr,*loc; int temp,k; for(k=0,loc=start;k<temp;k++) { loc=loc->next; if(loc==NULL) { printf("node in the list at less than one\n"); return; } } UNIT 1

  23. ptr=(NODE *)malloc(sizeof(NODE)); ptr->info=item; ptr->next=loc->next;; loc->next=ptr; } void main() { int choice,item,after; char ch; clrscr(); createmptylist(start); do { printf("1.Insert element at begin \n"); printf("2. insert element at end positon\n"); printf("3. insert specific the position\n"); printf("4.travers the list in order\n"); printf("5. exit\n"); UNIT 1

  24. printf("enter your choice\n"); scanf("%d",&choice); switch(choice) { case 1: printf("Enter the item\n"); scanf("%d",&item); insertatbegin(item); break; case 2: printf("Enter the item\n"); scanf("%d",&item); insert_at_end(item); break; case 3: printf("Enter the item\n"); scanf("%d",&item); insert_spe(start,item); break; UNIT 1

  25. case 4: printf("\ntravers the list\n"); traversinorder(start); break; case 5: return; } fflush(stdin); printf("do your want continous(y for yes)\n"); scanf("%c",&ch); }while((ch='y')||(ch='Y')); getch(); } UNIT 1

  26. THANKS UNIT 1

More Related