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trying to create a basic linked list

weelad (1)
for some reason I'm having trouble making a basic linked list.

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#include <iostream>

using namespace std;

struct node
{
    int data;
    node * next;
};

class List1
{
public:
    node * head;
    node * curr;
    int length;

List1()
{
    head = 0;
    curr = head;
}

void createNode()
{
    curr = new node;
    curr = curr->next;
    length++;
}


void printNodes()
{
    node * traveler;
    traveler = head;
    while (traveler != curr->next)
    {
        cout << traveler << '\n';
        traveler = traveler->next;
    }
}

};


trying to access head->next after creating at least two nodes keeps giving me errors. not sure why.
helios (17506)
Just follow your state mutations.

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(enter List1::List1())
    head = ?
    curr = ?

    (head = 0;)

    head = nullptr
    curr = ?

    (curr = head;)

    head = nullptr
    curr = nullptr
(leave List1::List1())

(enter List1::createNode())
    head = nullptr
    curr = nullptr
    
    (curr = new node)

    head = nullptr
    curr->data = ?
    curr->next = ?
    
    (curr = curr->next)
    
    head = nullptr
    curr = ?
(leave List1::createNode())

(enter List1::printNodes())
    head = nullptr
    curr = ?
    traveler = ?
    
    (traveler = head)
    
    head = nullptr
    curr = ?
    traveler = nullptr
    
    (while (traveler != curr->next))
    (Undefined behavior is triggered at this point. You attempted to dereference
    curr, which has an undefined value.)
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