CircularLinkedList.cpp

#include<iostream>

using namespace std;

class Node{
public:
    long data;
    Node* next;
    
    Node(long x)
    {
        data = x;
        next = NULL;
    }
};

long arr[100] = {0};

Node* createLL(){
    Node* head = NULL;
    Node* tail = NULL;
    
    while(true){
        long x;
        cin >> x;
        
        arr[x]++;
        
        if (x == -1) break;
        
        Node* curNode = new Node(x);
        if (head == NULL){
            // curNode is the first node of our list
            head = curNode;
            tail = curNode;
        }
        else{
            tail->next = curNode;
            tail = tail->next;
        }
    }
    return head;
}

void display(Node* head){
    Node* cur = head;
    while(cur != NULL){                 // while(cur)
        if(arr[cur->data] >= 1)
        {
            cout << cur->data << " ";
            arr[cur->data] = -1;
        }
        else if(arr[cur->data] == -1)
            break;
        cur = cur->next;
    }
}

int main()
{
    Node* head = createLL();
    display(head);
    
}