/******************************************************************************
* MPI tutorial example code: Blocking Send/Receive
* FILE: mpi_ping.c
* AUTHOR: Blaise Barney
* LAST REVISED:
******************************************************************************/
 #include "mpi.h"
 #include <stdio.h>

 int main(argc,argv)
 int argc;
 char *argv[];  {
 int numtasks, rank, dest, source, rc, tag=1;
 char inmsg, outmsg='x';
 MPI_Status Stat;

 MPI_Init(&argc,&argv);
 MPI_Comm_size(MPI_COMM_WORLD, &numtasks);
 MPI_Comm_rank(MPI_COMM_WORLD, &rank);

 if (rank == 0) {
   dest = 1;
   source = 1;
   rc = MPI_Send(&outmsg, 1, MPI_CHAR, dest, tag, MPI_COMM_WORLD);
   rc = MPI_Recv(&inmsg, 1, MPI_CHAR, source, tag, MPI_COMM_WORLD, &Stat);
   printf("Task %d sent and received from task %d\n",rank,dest);
   }

 else if (rank == 1) {
   dest = 0;
   source = 0;
   rc = MPI_Recv(&inmsg, 1, MPI_CHAR, source, tag, MPI_COMM_WORLD, &Stat);
   rc = MPI_Send(&outmsg, 1, MPI_CHAR, dest, tag, MPI_COMM_WORLD);
   printf("Task %d sent and received from task %d\n",rank,dest);
   }

 MPI_Finalize();
 }