#130 Added Doubly Linked List and #128 Circular Linked List in C++

data_structures/linked_lists/CircularListC++.cpp

@@ -0,0 +1,218 @@
+#include <iostream>
+
+using namespace std;
+
+template<class T>
+class CNode
+{
+	public:
+
+		CNode<T> *next;
+		T info;
+
+		CNode(const T& el, CNode *n=0)
+		{
+			info=el;
+			next=n;
+		}
+};
+
+template<class T>
+class CList
+{
+	public:
+
+		CNode<T> *tail;
+
+		CList()
+		{
+			tail=0;
+		}
+
+		~CList();
+
+		void addToTail(T);
+
+		T deleteFromTail();
+
+		void deleteNode(T);
+		bool isInList(T);
+
+		CList<T>* operator +(CList<T>*);
+
+	    void reverse();
+	    bool search(T el);
+
+	    void display(); 
+
+	    void addToPosition(CList<T>*, T, int);
+	    void deleteFromPosition(CList<T>* ,int);
+};
+
+template<class T>
+CList<T> :: ~CList()
+{
+  for(CNode<T> *p; !(tail!=0); )
+  {
+  	p=tail->next;
+  	delete tail;
+  	tail=p;
+  }
+
+}
+
+template<class T>
+void CList<T> :: addToTail(T el)
+{
+	if(tail==0)
+	{
+		tail=new CNode<T>(el);
+		tail->next=tail;
+	}
+	else
+	{
+		tail->next=new CNode<T>(el, tail->next);
+		tail=tail->next;
+	}
+}
+
+template<class T>
+T CList<T> :: deleteFromTail()
+{
+	CNode<T> *c=tail->next;
+	T h=tail->info;
+	if(tail==tail->next)
+	{
+		//T e=tail->info;
+		delete tail;
+		tail=0;
+		return h;
+	}
+	while(c->next!=tail)
+	{
+		c=c->next;
+	}
+	c->next=tail->next;
+	delete tail;
+	tail=c;
+	return h;
+}
+
+template<class T>
+void CList<T> :: deleteNode(T el)
+{
+	CNode<T> *tmp=tail, *pred;
+	if(el == tmp->info)
+	{
+		deleteFromTail();
+		return ;
+	}
+	while(tmp->next != tail && el != tmp->info)
+	{
+		pred=tmp;
+		tmp=tmp->next;
+	}
+	pred->next=tmp->next;
+	delete tmp;
+}
+
+template<class T>
+bool CList<T> :: search(T el)
+{
+	CNode<T> *tmp;
+	for(tmp=tail; tmp->next!=tail && !(tmp->info==el); tmp=tmp->next);
+        return tmp!=0;
+
+}
+
+template<class T>
+void CList<T> :: reverse()
+{
+	CNode<T> *prev=tail, *current=tail->next, *nexty=current->next, *temp, *temp2, *temp3;
+	while(current!=tail)
+	{
+		temp=current;
+		temp2=nexty;
+		temp3=nexty->next;
+		nexty->next=current;
+		current->next=prev;
+		prev=temp;
+		current=temp2;
+		nexty=temp3;
+	}
+}
+
+template<class T>
+void CList<T> :: display()
+{
+	if(tail==0)
+	{
+		cout<<"\nList is empty ";
+		return;
+	}
+	CNode<T> *c=tail->next;
+	cout<<"\n";
+	do
+	{
+		cout<<c->info<<" ";
+		c=c->next;
+	}while(c!=tail->next);
+}
+
+int main()
+{
+	CList<int> *C=new CList<int>();
+	int c;
+	char ch='y';
+	do
+	{
+		cout<<"\nMenu is : 1.addToTail   2.deleteFromTail   3.deleteNode    4.search    5.reverse : ";
+		cin>>c;
+		switch(c)
+		{
+			case 1:{  int i;
+					  cout<<"\nEnter the info value to be added to tail : ";
+					  cin>>i;
+					  C->addToTail(i);
+					  C->display();
+					  break;
+				   }
+
+		    case 2:{  cout<<(C->deleteFromTail())<<" is the deleted element ";
+		    		  C->display();
+				      break;
+			       }
+
+			case 3:{  int i;
+					  cout<<"\nEnter element to be deleted : ";
+					  cin>>i;
+					  C->deleteNode(i);
+					  C->display();
+				      break;
+			       }
+
+			case 4:{
+					  int i;
+					  cout<<"\nEnter element to be searched : ";
+					  cin>>i;
+					  int r= C->search(i);
+					  if(r==0)	cout<<"\nElement not found !!!";
+					  else 		cout<<"\nElement found !!!";
+				      break;
+				   }
+
+			case 5:{
+				 	  cout<<"\nThe reverse List is : ";
+					  C->reverse();
+					  C->display();  
+					  break;
+				   }
+		}
+
+		cout<<"\nDo you want to do more (y/n) ???  ";
+		cin>>ch;
+
+	}while(ch=='y' || ch=='Y');
+
+	return 0;
+}