#include <iostream>

struct node
{
	node	*next;
	int		value;

	node (int i)
	{
		value = i;
		next = nullptr;
	}
};

/**
* Print the addresses and values of each node starting with p.
*
* @param p The address of the first node in the list to print.
********************************************************************/
static void print_list(node *p)
{
	std::cout << "************ list **************" << std::endl;

	while(p)
	{
		std::cout << "node: " << p << std::endl;		// print the address of the node
		std::cout << "   next=" << p->next << std::endl;
		std::cout << "  value=" << p->value << std::endl;

		p = p->next;	// prepare to print the 'next' node
	}
}


/**
* Insert a node into the list.
*
* @param pp		A pointer to the next pointer in the node preceeding the new node.
* @param pn		A pointer to the node to insert.
*****************************************************************/
static void insert_node(node **pp, node *pn)
{
	pn->next = *pp;
	*pp = pn;
}

/**
* Demonstrate singly-linked list insertions.
*****************************************************************/
int main()
{
	node *phead = nullptr;

	print_list(phead);

	std::cout << "*** insert a new node into an empty list" << std::endl;
	node *pn1 = new node(1);
	insert_node(&phead, pn1);
	print_list(phead);		// 1


	std::cout << "*** insert a new node at the head of a non-empty list" << std::endl;
	node *pn2 = new node(2);
	insert_node(&phead, pn2);
	print_list(phead);		// 2 -> 1


	std::cout << "*** insert a new node at the tail of a non-empty list (after #1)" << std::endl;
	node *pn3 = new node(3);
	insert_node(&pn1->next, pn3);
	print_list(phead);		// 2 -> 1 -> 3


	std::cout << "*** insert a new node into the middle of the list after node #1" << std::endl;
	node *pn4 = new node(4);
	insert_node(&pn1->next, pn4);
	print_list(phead);		// 2 -> 1 -> 4 -> 3

	return 0;
}