Insert data ID Name in this code

#include
using namespace std;

// A linked list node
struct Node
{
int data;
struct Node* next;
};

//insert a new node in front of the list
void insertData(struct Node** head, int node_data)
{
/* 1. create and allocate node /
struct Node
newNode = new Node;

/* 2. assign data to node */
newNode->data = node_data;

/* 3. set next of new node as head */
newNode->next = (*head);

/* 4. move the head to point to the new node */
(*head) = newNode;

}

//insert new node after a given node
void insertAfter(struct Node* prev_node, int node_data)
{
/*1. check if the given prev_node is NULL */
if (prev_node == NULL)
{
cout << “the given previous node is required,cannot be NULL”; return;
}

/* 2. create and allocate new node */
struct Node* newNode = new Node;

/* 3. assign data to the node */
newNode->data = node_data;


/* 4. Make next of new node as next of prev_node */
newNode->next = prev_node->next;

/* 5. move the next of prev_node as new_node */
prev_node->next = newNode;

}

/* insert new node at the end of the linked list /
void insertTail(struct Node
* head, int node_data)
{
/* 1. create and allocate node /
struct Node
newNode = new Node;

struct Node* last = *head; /* used in step 5*/

/* 2. assign data to the node */
newNode->data = node_data;

/* 3. set next pointer of new node to null as its the last node*/
newNode->next = NULL;

/* 4. if list is empty, new node becomes first node */
if (*head == NULL)
{
    *head = newNode;
    return;
}

/* 5. Else traverse till the last node */
while (last->next != NULL)
    last = last->next;

/* 6. Change the next of last node */
last->next = newNode;
return;

}

// display linked list contents
void displayList(struct Node* node)
{
//traverse the list to display each node
while (node != NULL)
{
cout << node->data << endl;
node = node->next;
}

if (node == NULL)
    cout << "null";

}
/* main program for linked list*/
int main()
{
/* empty list /
struct Node
head = NULL;

// Insert Data to the list
insertTail(&head, 40);
insertTail(&head, 10);
insertData(&head, 30);
insertData(&head, 20);
insertAfter(head->next, 50);

cout << "Final linked list: " << endl;
displayList(head);

return 0;

}