#include <stdio.h>
#include <mpi.h>

#define BUFSIZE		64
int			buf[BUFSIZE];

int
main(argc, argv)

int			argc;
char			*argv[];

{
	int		size, rank;
	MPI_Status	status;

	printf("System started!");

/*
 * Initialize MPI.
 */
	MPI_Init(&argc, &argv);
/*
 * Error check the number of processes.
 * Determine my rank in the world group.
 * The sender will be rank 0 and the receiver, rank 1.
 */
	MPI_Comm_size(MPI_COMM_WORLD, &size);
	
	if (size < 2) {
		printf("Need at least 2 processes.\n");
		MPI_Finalize();
		return(1);
	}
	
	MPI_Comm_rank(MPI_COMM_WORLD, &rank);
/*
 * As rank 0, send a message to rank 1.
 */
	if (0 == rank) {
		MPI_Send(buf, BUFSIZE, MPI_INT, 1, 11, MPI_COMM_WORLD);
		printf("rank %d sent message\n", rank);
	}
/*
 * As rank 1, receive a message from rank 0.
 */
	else if (1 == rank) {
		MPI_Recv(buf, BUFSIZE, MPI_INT, 0, 11, MPI_COMM_WORLD,
				&status);
		printf("rank %d received message\n", rank); 
	}

	MPI_Finalize();
	return(0);
}