/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */

/*

 *  (C) 2001 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

#include "mpi.h"

#include <stdio.h>

#include <string.h>

#define BUFLEN 512

int main(int argc, char *argv[])

{

    int myid, numprocs, next, namelen;

    char buffer[BUFLEN], processor_name[MPI_MAX_PROCESSOR_NAME];

    MPI_Status status;

    MPI_Init(&argc,&argv);

    MPI_Comm_size(MPI_COMM_WORLD,&numprocs);

    MPI_Comm_rank(MPI_COMM_WORLD,&myid);

    MPI_Get_processor_name(processor_name,&namelen);

    fprintf(stderr,"Process %d on %s\n", myid, processor_name);

    fprintf(stderr,"Process %d of %d\n", myid, numprocs);

    strcpy(buffer,"hello there");

    if (myid == numprocs-1)

	next = 0;

    else

	next = myid+1;

    if (myid == 0)

    {

        printf("%d sending '%s' \n",myid,buffer);fflush(stdout);

	MPI_Send(buffer, strlen(buffer)+1, MPI_CHAR, next, 99, MPI_COMM_WORLD);

	printf("%d receiving \n",myid);fflush(stdout);

	MPI_Recv(buffer, BUFLEN, MPI_CHAR, MPI_ANY_SOURCE, 99, MPI_COMM_WORLD,

		 &status);

	printf("%d received '%s' \n",myid,buffer);fflush(stdout);

	/* mpdprintf(001,"%d receiving \n",myid); */

    }

    else

    {

        printf("%d receiving  \n",myid);fflush(stdout);

	MPI_Recv(buffer, BUFLEN, MPI_CHAR, MPI_ANY_SOURCE, 99, MPI_COMM_WORLD,

		 &status);

	printf("%d received '%s' \n",myid,buffer);fflush(stdout);

	/* mpdprintf(001,"%d receiving \n",myid); */

	MPI_Send(buffer, strlen(buffer)+1, MPI_CHAR, next, 99, MPI_COMM_WORLD);

	printf("%d sent '%s' \n",myid,buffer);fflush(stdout);

    }

    MPI_Barrier(MPI_COMM_WORLD);

    MPI_Finalize();

    return (0);

}