Doubly Linked List(DLL) deletion operation, Delete functions/algorithms

Deletion:- To remove an element from a given Singly Linked List is known as Deletion. It is of four types-

डिलीशन:- डबली लिंक्ड लिस्ट से किसी एलिमेंट को हटाना, डिलीशन कहलाता है। यह चार प्रकार से किया जा सकता है- 

a) Delete first node (पहला नोड हटाना )

 

//Delete First Node from DLL

void deletefirstdll(){

clrscr();

if(first==NULL){

printf("Underflow Condition\n");

getch();

return;

}

n=first;

if(first->next==NULL){

first=last=NULL;}

else{

first=first->next;

first->back=NULL;}

printf("first node %d is deleted\n",n->info);

getch();

free(n);

return;

}

b) Delete last node (अंतिम नोड हटाना)

//Delete Last Node from DLL

void deletelastdll(){

clrscr();

if(last==NULL){

printf("Underflow Condition\n");

getch();

return;

}

n=last;

if(last->back==NULL){

first=last=NULL;}

else{

last=last->back;

last->next=NULL;}

printf("last node %d is deleted\n",n->info);

getch();

free(n);

return;

}

c) Delete a node after given location (किसी दी गयी स्थिति के पश्चात नोड को हटाना)

 

//Delete a Node after given Location from DLL

void deleteafterlocdll(NODE *loc){

clrscr();

if(first==NULL){

printf("Underflow Condition\n");

getch();

return;

}

if(loc==last){

printf("loc is last node\ndeletion is not possible\n");

getch();

return;

}

if(loc->next=last){

printf("location is second last node\nChoose option delete last node in dll\n");

getch();

return;

}

else{

n=loc->next;

loc->next->next->back=loc;

loc->next=loc->next->next;

}

printf("Node= %d after given location  is deleted\n",n->info);

getch();

free(n);

return;

}

 

d) Delete a node before given location  (किसी दी गयी स्थिति के पुर्व नोड को हटाना)

//Delete a Node before given Location from DLL

void deletebeforelocdll(NODE *loc){

if(last==NULL){

printf("Underflow Condition\n");

getch();

return;

}

if(loc==first){

printf("loc is first node\ndeletion is not possible\n");

getch();

return;

}

if(loc->back=first){

printf("location is second node\nChoose option delete first node in dll\n");

getch();

return;

}

else{

n=loc->back;

loc->back->back->next=loc;

loc->back=loc->back->back;

printf("Node= %d before given location  is deleted\n",n->info);

getch();

free(n);

return;

}