Doubly Linked List in C++ added.

data-structures/Circular_Linked_List.cpp

@@ -0,0 +1,57 @@
+#include <iostream>
+#include <conio.h>
+
+using namespace std;
+
+int main()
+{
+
+struct node{
+	int info;
+	node *next;
+}*ptr,*head,*start;
+
+int c=1,data;
+
+ptr=new node;
+ptr->next=NULL;
+
+start=head=ptr;
+
+while(c<3 && c>0){
+	cout<<"1.Insert\n2.Link List\n";
+	cin>>c;
+
+	switch(c){
+		case 1:
+			cout<<"Enter Data\n";
+			cin>>data;
+
+			ptr=new node;
+			ptr->next=start;
+			ptr->info=data;
+
+			head->next=ptr;
+			head=ptr;
+
+		break;
+
+		case 2:
+			ptr=start->next;
+
+			while(ptr!=start && ptr!=NULL){
+				cout<<ptr->info<<"->";
+				ptr=ptr->next;
+			}
+			cout<<"\n";
+		break;
+
+		default:
+			cout<<"Wrong Choice\nExiting...\n";
+	}
+
+}
+
+getch();
+return 0;
+}

data-structures/Doubly_Linked_List.cpp

@@ -0,0 +1,93 @@
+#include <iostream>
+#include <conio.h>
+
+using namespace std;
+int main()
+{
+struct node{
+	int info;
+	node *left,*right;
+}*ptr,*start,*last,*save;
+
+int c=1,i=0,data,item;
+start=last=NULL;
+
+while(c<4 && c>0){
+	cout<<"1.Insert\n2.Deletion\n3.Link List\n";
+	cin>>c;
+
+	switch(c){
+		case 1:
+		cout<<"Enter Data\n";
+		cin>>data;
+
+		ptr=new node;
+		ptr->info=data;
+		ptr->left=last;
+		ptr->right=NULL;
+
+		if(start==NULL){
+			start=last=ptr;
+		}
+
+		else{
+			last->right=ptr;
+			last=ptr;
+		}
+		break;
+
+		case 2:
+		if(start==NULL){
+			cout<<"Underflow\n";
+		}
+
+		else{
+			cout<<"Enter Item to be Deleted\n";
+			cin>>item;
+			ptr=start;
+
+			while(ptr!=NULL){
+				if(ptr->info==item){
+					i++;
+					if(ptr==start){
+						start->left=NULL;
+						start=start->right;
+					}
+
+					else{
+						ptr->left->right=ptr->right;
+						ptr->right->left=ptr->left;
+					}
+				delete ptr;
+				cout<<"Item Deleted\n";
+				}
+				ptr=ptr->right;
+			}
+
+			if(i==0){
+				cout<<"Item Does not exist\n";
+			}
+			i=0;
+		}
+		break;
+
+		case 3:
+
+		ptr=start;
+
+		while(ptr!=NULL){
+			cout<<ptr->info<<"->";
+			ptr=ptr->right;
+		}
+		cout<<"\n";
+		break;
+
+		default:
+		cout<<"Wrong Choice\nExiting...\n";
+	}
+
+}
+
+getch();
+return 0;
+}