Delete node from Linked List C++ - c++

Question

I am working on iterative delete function that deletes node from a linked list, I think that the code is supposed to work fine. But when I can't use "delete" to delete the first Node of the List.
The code is:
#include
using namespace std;
struct Node
{
int data;
Node* next;
};
Node* GetNewNode(int data)
{
Node* newNode = new Node;
newNode->data = data;
newNode->next = NULL;
return newNode;
}
Node* Insert(Node *root, int data)
{
if (root == NULL)
{
root = GetNewNode(data);
}
else
root->next = Insert(root->next, data);
return root;
}
void Delete_k(Node *root, int k)
{
int i = 0;
Node* P = new Node;
if (k == 1)
{
P = root;
root = root->next;
delete P;
}
else
{
for (int i = 1; i <= k - 2; i++)
{
root = root->next;
}
root->next = root->next->next;
}
}
void Output(Node* root)
{
if (root == NULL)
{
root = root->next;
}
while (root != NULL)
{
cout << root->data << " ";
root = root->next;
}
}
int main()
{
int n, a, pos;
Node* root = NULL;
cout << "Input your list hear: ";
cin >> n;
while (n > 0)
{
root = Insert(root, n);
cin >> n;
}
Output(root);
cout << "\nDelete Pos?: ";
cin >> pos;
Delete_k(root, pos);
Output(root);
}
I have problem in this
void Delete_k(Node *root, int k)
{
int i = 0;
Node* P = new Node;
if (k == 1)
{
P = root;
root = root->next;
delete P;
}
else
{
for (int i = 1; i <= k - 2; i++)
{
root = root->next;
}
root->next = root->next->next;
}
}

Answer 1

The problem:
void Delete_k(Node *root, int k)
The value at root is pass by reference, but the pointer to it is not.
Result: Delete_k's root is a copy of main's root. Delete_K's root gets repointed and deleted. Main's root now points at garbage memory. End game program.
Solution:
Provide a reference to the root pointer so that it doesn't get copied.
void Delete_k(Node *& root, int k)
Or return root from Delete_k.
Node * Delete_k(Node * root, int k)
{
//existing code
return root;
}