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

#define BUFLEN 512

int main(argc,argv)
int argc;
char *argv[];
{
    int i, myid, numprocs, next;
    char buffer[BUFLEN];
    MPI_Status status;

    MPI_Init(&argc,&argv);
    MPI_Comm_size(MPI_COMM_WORLD,&numprocs);
    MPI_Comm_rank(MPI_COMM_WORLD,&myid);

    strcpy(buffer,"hello there");
    if (myid == numprocs-1)
	next = 0;
    else
	next = myid+1;

    if (myid == 0)
    {
	printf("%d sending '%s' \n",myid,buffer);
	MPI_Send(buffer, strlen(buffer)+1, MPI_CHAR, next, 99, MPI_COMM_WORLD);
	printf("%d receiving \n",myid);
	MPI_Recv(buffer, BUFLEN, MPI_CHAR, MPI_ANY_SOURCE, 99, MPI_COMM_WORLD,
		 &status);
	printf("%d received '%s' \n",myid,buffer);
    }
    else
    {
	printf("%d receiving  \n",myid);
	MPI_Recv(buffer, BUFLEN, MPI_CHAR, MPI_ANY_SOURCE, 99, MPI_COMM_WORLD,
		 &status);
	printf("%d received '%s' \n",myid,buffer);
	MPI_Send(buffer, strlen(buffer)+1, MPI_CHAR, next, 99, MPI_COMM_WORLD);
	printf("%d sent '%s' \n",myid,buffer);
    }
    MPI_Barrier(MPI_COMM_WORLD);
    MPI_Finalize();
}