Data-Structures/loop.cpp at master · ard1498/Data-Structures · GitHub

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//loop applied successfully......
#include<iostream>

usingnamespacestd;

structnode{
int data;
	node *next;
node(int data){
this->data=data;
this->next=NULL;
	}
};

classlinked_list{
	node * head;
 node * start;
public:
linked_list(){
 head=NULL;
 start=NULL;
	}

voidinsertion(int item){
if(head==NULL){
 head=newnode(item);
 start=head;
return;
 }

 node *np = newnode(item);
 start->next=np;
 start=np;
	}

voidmakeloop(){
if(head!=NULL){
 start->next=start;
 }
	}

voidcheckloop(){
int flag=0;
 node * ptr1 = head;
 node * ptr2 = head;
while(ptr2 != NULL && ptr2->next != NULL){
 ptr1=ptr1->next;
 ptr2=ptr2->next->next;
if(ptr1==ptr2){
 flag=1;
 cout<<"\nloop exists.";
break;
 }
 }
if(flag==0)
 cout<<"\ndoes not exists.";
return;
 }

voiddisplay(){
 node *temp=head;
if(temp==NULL){
 cout<<"\nlist is empty ....";
return;
 }
while(temp!=NULL){
 cout<<temp->data<<"\t";
 temp=temp->next;
 }
return;
	}
};

intmain(){
 linked_list l1;
 l1.insertion(9);
 l1.insertion(2);
 l1.insertion(3);
 l1.insertion(4);
 l1.insertion(7);
 l1.makeloop();
 l1.checkloop();
return0;
}