//DOUBLY LINKED LIST #include using namespace std; struct node { int data; node* prev; node* next; }; node * head = NULL; int n=0; void add (int data,int x =n) { node* temp1 =new node; temp1 -> data = data; if(head == NULL) { temp1 -> next = head; temp1 -> prev = head; head=temp1; n++; return; } node * temp2 =head; for(int i=1;inext; } temp1->next = temp2 ->next; temp2->next = temp1; temp1->prev = temp2; n++; } void print() { node* t= head; while(t!=NULL) { cout<<"\t"<data; t=t->next; } } void printr() { node* t = head; while(t->next!=NULL) { t=t->next; } cout<<"\t"<data; t=t->prev; while(t!=NULL) { cout<<"\t"<data; t=t->prev; } } int pos(int x) { node * t= head; for(int i=1;inext; if(t->data == x) { return i+1; } } return 0; } void fval(int x) { node * t= head; if(x<=n) { for (int i=1;inext; } cout<<"VALUE AT "<data; } else { cout<<"ENTER PROPER INDEX"; } } void del(int i) { if(i==1) { head=head->next; head->prev=NULL; } if((i<1)||(i>n)) { cout<<"\nENTER A PROPER INDEX"; } else { node * t= head; for(int j=1 ; jnext; } t=t->next; t->prev=t->prev->prev ; } } /*void rev() { node *t; do { t = head; head = head ->next; t->next = t->prev; t->prev = head; } while(head != NULL); head=t; }*/ node * rev(node * t) { node * t1 = t->next; t->next = t->prev; t->prev = t1; if(t->prev==NULL) { return t; } return rev(t->prev); } int main() { int m,i,x; do { cout<<"\n\nENTER YOUR CHOICE.....\n1.INSERT AT END \n2.INSERT AT Nth POSITION \n3.FIND BY VALUE \n4.FIND BY POSITION \n5.DISPLAY \n6.DISPLAY REVERSE \n7.DELETE BY POSITION \n8.DELETE BY VALUE \n9.REVERSE \n10.EXIT "; cin>>m; switch (m) { case 1 : cout<<"\n\n1.INSERT AT END \nENTER THE DATA : "; cin>>x; cout<>x>>i; cout<>x; cout<0) {cout<>i; cout<>i; del(i); break; case 8 : cout<<"\n\n3.DELETE BY VALUE \nENTER THE VALUE TO DELETE : "; cin>>x; i=pos(x); del(i); break; case 9 : cout <<"\n\n5.REVERSING \nYOUR REVERSED ARRAY : \n"; //rev(); head=rev(head); print; break ; default : return 0; } }while(m<=10); return 0; }

doubly linkedlist