Linked List Insertion in C++

#include< iostream>
using namespace std;
class Node
{
  public:
  int val;
  Node *next;
};
void insertAtBeginning (Node ** head, int val)
{
  // dynamically create memory for this newNode
  Node *newNode = new Node ();
  newNode->val = val;
  newNode->next = *head;
  *head = newNode;
  cout << newNode->val << " inserted" << endl;
  }
  void insertAtLast (Node ** head, int val) {
      Node *newNode = new Node ();
      newNode->val = val;
  // Last node always pointst to NULL
  newNode->next = NULL;
  // If Linked List was empty
  if (*head == NULL)
  {
    *head = newNode;
    cout << newNode->val << " inserted" << endl;
    return;
    }
    Node *tempNode = *head; // reach to the last node of Linked List
    while (tempNode->next != NULL)
    tempNode = tempNode->next;
  // assign last node's next to this newNode
  tempNode->next = newNode;
  cout << newNode->val << " inserted" << endl;
  } // required for insertAfterNthNode
  int getCurrSize (Node * node) {
      int size = 0;
      while (node != NULL) {
          node = node->next;
      size++;
    }
  return size;
}
void insertAfterNthNode (int n, int val, Node ** head)
{
  int size = getCurrSize (*head);
  // Negative Position Insertions not possible
  // Can't insert if position to insert is greater than size of Linked List
  if (n < 0 || n > size)
    cout << "Invalid position to insert";
    if (n == 0)
    {
        insertAtBeginning(head, val);
    }
    else
    {
        Node *newNode = new Node ();
        newNode->val = val;
        newNode->next = NULL;
      // tempNode used to traverse the Linked List
      Node *tempNode = *head;
      // traverse till the nth node
      while (--n)
	tempNode = tempNode->next;
      // assign newNode's next to nth node's next
      newNode->next = tempNode->next;
      // assign nth node's next to this new node
      tempNode->next = newNode;
      // newNode inserted
      cout << newNode->val << " inserted" << endl;
    }
}
void display (Node * node)
{
  cout << "\n";
  // as linked list will end when Node is Null
  while (node != NULL)
    {
      cout << node->val << " "; node = node->next;
    }
  cout << "\n" << endl;
}
int main ()
{
  Node *head = NULL;
  insertAtBeginning (&head, 12);
  insertAtBeginning (&head, 11);
  insertAtBeginning (&head, 10);
  display (head);
  insertAtLast (&head, 13);
  insertAtLast (&head, 14);
  insertAtLast (&head, 16);
  display (head);
  //Inserts data: 15 after 5th node
  insertAfterNthNode (5, 15, &head);
  insertAfterNthNode (0, 9, &head);
  display (head);
  return 0;
}

Run

#include<iostream>
using namespace std;

class Node
{
public:
  int data;
  Node *next;
};

int calcSize (Node * node)
{
  int size = 0;

  while (node != NULL)
    {
      node = node->next;
      size++;
    }
  return size;
}

void insertStart (Node ** head, int data)
{

  Node *newNode = new Node ();

  newNode->data = data;
  newNode->next = *head;

  //changing the new head to this freshly entered node
  *head = newNode;

}

void insertLast (Node ** head, int data)
{

  Node *newNode = new Node ();

  newNode->data = data;
  newNode->next = NULL;

  //need this if there is no node present in linked list at all
  if (*head == NULL)
    {
      *head = newNode;
      return;
    }

  struct Node *temp = *head;

  while (temp->next != NULL)
    temp = temp->next;

  temp->next = newNode;
}

void insertPosition (int pos, int data, Node ** head)
{
  int size = calcSize (*head);

  //If pos is 1 then should use insertStart method
  //If pos is less than or equal to 0 then can't enter at all
  //If pos is greater than size then bufferbound issue
  if (pos < 1 || size < pos)
    {
      printf ("Can't insert, %d is not a valid position\n", pos);

    }
  else
    {
      Node *temp = *head;
      Node *newNode = new Node ();

      newNode->data = data;
      newNode->next = NULL;

      while (--pos)
	{
	  temp = temp->next;
	}
      //(25)->next = 10 as 12->next is 10 
      newNode->next = temp->next;
      // (12)->next = 25
      temp->next = newNode;
      //new node added in b/w 12 and 10
    }
}

void display (Node * node)
{

  //as linked list will end when Node is Null
  while (node != NULL)
    {
      cout << node->data << " ";
      node = node->next;
    }
  cout << endl;
}

int main ()
{

  Node *head = NULL;

  /*Need & i.e. address as we
     need to change head address only needs to traverse
     and access items temporarily
   */
  insertStart (&head, 12);
  insertStart (&head, 16);
  insertStart (&head, 20);

  insertLast (&head, 10);
  insertLast (&head, 14);
  insertLast (&head, 18);
  insertLast (&head, 11);

  //Inserts after 3rd position
  insertPosition (3, 25, &head);

  /*No need for & i.e. address as we do not
     need to change head address
   */
  display (head);
  return 0;
}