#include <stdio.h>
#define N 500		/* N is the number of rounds */
#define B 50		/* B is the message size, in bytes */
 
/* This is a ping-pong program.  */
/* It sends a message back and forth "N" times between two entities. */ 
/* Adapted for Parsec v.1.0 on 8-27-97 by Monnica Terwilliger */

/* Declare global message types and entities */

message other_player {ename name;};
message ball {char size[B];};

entity player(int);

/* Driver creates players and initiates game  */

entity driver ()
{
	ename Jack, Jill;
	char gameball[B];
	
	Jack = new player (1) at 1;
	Jill = new player (0) at 2;

	/* Send opponent's name to each entity */

	send other_player {Jill} to Jack;		
	send other_player {Jack} to Jill;

	/* Start the ping-pong game */

	send ball {gameball} to Jack;
}

entity player (int first_player)
{	int trips;
	char gameball[B];
	ename opponent;

	/* Wait to receive opponent's name */

	receive (other_player his)		/* "his" is a temporary variable */
		opponent = his.name;

	/* Wait for the message then send it back to the opponent */

	for (trips=1; trips < N; ++trips)
		receive (ball signal)
			send ball {gameball} to opponent;

	/* Game over -- don't return the message */

	if (first_player)
	{    printf ("Game over after %d rounds and %d byte ball size!\n",N,B);
	     receive (ball signal) 
			pc_exit(1);
	}
}