Sample C code:

 int main(argc,argv)
 int argc;
 char *argv[];  {
 int numtasks, rank, dest, source, rc, count, 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);
   }

 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);
   }

 rc = MPI_Get_count(&Stat, MPI_CHAR, &count);
 printf("Task %d: Received %d char(s) from task %d with tag %d \n",
        rank, count, Stat.MPI_SOURCE, Stat.MPI_TAG);

 MPI_Finalize();
 }