//DISPLAY 13.4 Function to Add a Node at the Head of a Linked List
//Function Declaration
struct Node
{
    int data;
    Node *link;
};

typedef Node* NodePtr;

void head_insert(NodePtr& head, int the_number);
//Precondition: The pointer variable head points to
//the head of a linked list.
//Postcondition: A new node containing the_number
//has been added at the head of the linked list.
Function Definition
void head_insert(NodePtr& head, int the_number)
{
    NodePtr temp_ptr;
    temp_ptr = new Node;

    temp_ptr->data = the_number;

    temp_ptr->link = head;
    head = temp_ptr;
}