class	list_node {

	int	data;
	list_node	link;

	// creat node with data 0 and null pointer
	list_node()
	{
		this.data=0;
		this.link=null;		
	}

	// creat node with the given data and null pointer
	list_node(int data)
	{
		this.data=data;
		this.link=null;		
	}

	// creat node with the given data and points to the given list_node
	list_node(int data, list_node link)
	{
		this.data=data;
		this.link=link;		
	}
}