Cannot understand the error

#1

this is my code for circular linked list challenge –https://ide.codingblocks.com/s/328343.

#2

First you have to input list in the given format and create a cycle from where the values start repeating. And then apply your cycle function on it.
Use the following code segment to input the cyclic linked list -

void buildList(node*&head)
{
    int x;
    cin>>x;

    map<int,int> a;

    while((x != -1) && (!a[x]))
    {
        a[x]++;
        insertAtTail(head, x);
        cin>>x;
    }
    
    if(x==-1)
    return;

    node*last = head;
    while(last->next!=NULL)
        last = last->next;

    node*temp = head;
    while(temp->data != x)
        temp = temp->next;

    last->next = temp;

    while(x!=-1)
    cin>>x;
}