Double linked list

A Full Menu Driven Program On Double Linked List Coded In C Language using Structure

1. DOUBLE LINKED LIST A Menu Driven Program In C

2. The Basic Declarations #include< stdio.h > #include< stdlib.h > void mainmenu (), create(), display(), insert(), insert_first (), insert_between (), insert_end (), deletion(), delete_first (), delete_position (), delete_end (), sort(),reverse(),find(); int count(); struct node { struct node * prev ; int info; struct node *next; }; typedef struct node NODE ; NODE *start=NULL; int main() { mainmenu (); }

3. The Mainmenu Function void mainmenu () { int choice,x ; while(1) { printf ("\n----MAIN MENU----\n"); printf ("1. Create.\n"); printf ("2. Display.\n"); printf ("3. Insert.\n"); printf ("4. Count.\n"); printf ("5. Delete.\n"); printf ("6. Sorting.\n"); printf ("7. Reverse.\n"); printf ("8. Find.\n"); printf ("9. Exit.\n"); printf ("Enter choice: "); scanf ("% d",&choice ); switch(choice) { case 1: create(); break ; case 2: display(); break ; case 3: insert(); break ; case 4: x=count(); printf ("The number of elements are % d",x ); break; case 5: deletion(); break ; case 6: sort(); break ; case 7: reverse (); break ; case 8: find(); break ; case 9: exit(0); break ; default: printf ("Enter a valid choice."); } } }

4. Creation Of Nodes void create() { NODE *temp, *traverse; int iData ; temp=(NODE*) malloc ( sizeof (NODE)); temp-> prev =NULL; temp->next=NULL; printf ("Enter an integer value: "); scanf ("%d",& iData ); temp->info= iData ; if(start==NULL) { start=temp; } else { traverse=start; while(traverse->next!=NULL) { traverse=traverse->next; } traverse->next=temp; temp-> prev =traverse; } }

5. Display Of The Nodes void display() { NODE *traverse; if(start==NULL) { printf ("There are no nodes to be displayed. The list is empty .\n"); } else { traverse=start; printf ("The linked list is: "); while(traverse!=NULL) { printf ("%d ",traverse->info); traverse=traverse->next; } } }

6. The Insert Menu void insert() { int choice; while(1) { printf ("\n---Insert Menu---\n"); printf ("1. Insert at first position.\n"); printf ("2. Insert in between.\n"); printf ("3. Insert at the end.\n"); printf ("4. Go to main menu\n"); printf ("5. Exit\n"); printf ("Enter choice: "); scanf ("% d",&choice ); switch(choice) { case 1: insert_first (); break ; case 2: insert_between (); break ; case 3: insert_end (); break ; case 4: mainmenu (); break ; case 5: exit(0); break ; default: printf ("Enter a valid choice."); } } }

7. Insert Node At The First Position void insert_first () { NODE *temp; if(start==NULL) { printf ("List is empty. Create as the first node.\n"); create(); } else { int iData ; temp=(NODE *) malloc ( sizeof (NODE)); temp-> prev =NULL; temp->next=NULL; printf ("Enter an integer value: "); scanf ("%d",& iData ); temp->info= iData ; start-> prev =temp; temp->next=start; start=temp; printf ("Node inserted at first position.\n"); } display(); }

8. Insert Node At Any Position void insert_between () { if(start==NULL) { printf ("List is empty. Create as the first node.\n"); create(); } else { int iPosition,iCount,iLoop,iData ; printf ("Enter the position where you want to insert: "); scanf ("%d",& iPosition ); iCount =count(); if( iPosition > iCount ) { printf ("There are %d elements.\n", iCount ); } else { NODE *temp,*traverse; traverse=start; printf ("Enter an integer value: "); scanf ("%d",& iData ); temp = (NODE *) malloc ( sizeof (NODE)); temp-> prev =NULL; temp->info= iData ; temp->next=NULL; for( iLoop =0;iLoop<iPosition-2;iLoop++) { traverse=traverse->next; } temp-> prev =traverse; temp->next=traverse->next; traverse->next-> prev =temp; traverse->next=temp; printf ("Node inserted at position %d.\n", iPosition ); } } display(); }

9. Insert Node At The End void insert_end () { if(start==NULL) { printf ("List is empty. Create as the first node.\n"); create(); } else { create(); printf ("Node inserted at the end.\n"); } display(); }

10. Counting Of Nodes int count() { int iCount =0; NODE *traverse; traverse=start; while(traverse!=NULL) { traverse=traverse->next; iCount ++; } return iCount ; }

11. The Delete Menu void deletion() { int choice; while(1) { printf ("\n---Delete Menu---\n"); printf ("1. Delete first node.\n"); printf ("2. Delete last node.\n"); printf ("3. Delete by position.\n"); printf ("4. Go to main menu\n"); printf ("5. Exit\n"); printf ("Enter choice: "); scanf ("% d",&choice ); switch(choice) { case 1: delete_first (); break ; case 2: delete_end (); break ; case 3: delete_position (); break ; case 4: mainmenu (); break ; case 5: exit(0); break ; default: printf ("Enter a valid choice."); } } }

12. Delete The First Node void delete_first () { NODE * delete_node ; if(start==NULL) { printf ("There are no nodes to be deleted. The list is empty .\n"); } else { delete_node =start; start=start->next; free( delete_node ); printf ("The first node is deleted.\n"); } display(); }

13. Delete The Last Node void delete_end () { NODE * delete_node , *traverse; if(start==NULL) { printf ("There are no nodes to be deleted. The list is empty .\n"); } else { traverse=start; while(traverse->next->next!=NULL) { traverse=traverse->next; } delete_node =traverse->next; traverse->next=NULL; free( delete_node ); printf ("The last node is deleted.\n"); } display(); }

14. Delete Node At Any Position void delete_position () { if(start==NULL) { printf ("There are no nodes to be deleted. The list is empty.\n"); } else { NODE *traverse, * delete_node ; int iPosition , iLoop , iCount ; printf ("Enter the position to be deleted: "); scanf ("%d",& iPosition ); iCount =count(); if( iPosition > iCount ) { printf ("There are %d elements.\n", iCount ); } else { traverse=start; for( iLoop =0;iLoop<iPosition-2;iLoop++) { traverse=traverse->next; } delete_node =traverse->next; delete_node ->next-> prev =traverse; traverse->next= delete_node ->next; free( delete_node ); printf ("Node deleted at position %d.\n", iPosition ); } } display(); }

15. Sorting void sort() { static NODE *traverse1; traverse1=start; NODE *traverse2; int iOuter_Loop,iInner_Loop,iCount,iTemp ; iCount =count(); for( iOuter_Loop =0;iOuter_Loop<iCount-1;iOuter_Loop++) { traverse2=traverse1->next; for( iInner_Loop =iOuter_Loop+1;iInner_Loop< iCount;iInner_Loop ++) { if(traverse1->info>traverse2->info) { iTemp =traverse1->info; traverse1->info=traverse2->info; traverse2->info= iTemp ; } traverse2=traverse2->next; } traverse1=traverse1->next; } printf ("Nodes sorted\n"); display(); }

16. Reversal Of The List void reverse() { NODE *previous, *current; previous=start; current=previous->next; previous-> prev =current; previous->next=NULL; while(current!=NULL) { current-> prev =current->next; current->next=previous; previous=current; current=current-> prev ; } start=previous; printf ("Nodes reversed\n"); display(); }

17. Searching void find() { int iData ; NODE *traverse; printf ("Enter a number to be searched: "); scanf ("%d",& iData ); traverse=start; while(traverse!=NULL) { if(traverse->info== iData ) { printf ("Element found."); return; } else { traverse=traverse->next; } } printf ("Element not found."); }

18. Presented By: Sayantan Sur Thank You