Paying homage to the master

The last part of the code does not introduce any new elements. It is basically a reversal of the first send-receive operation. This time the slave processes send some information about themselves to the master, and the master having received that information prints it on standard output.

if (! i_am_the_master) {
   sprintf (char_buffer, "Greetings to the master (%s, %d) from (%s, %d)",
            host_name, host_rank, my_node_name, my_rank);
   MPI_Send (char_buffer, strlen(char_buffer) + 1, MPI_CHAR, host_rank, 
             2002, MPI_COMM_WORLD);
}
else {
   for (source = 0; source < pool_size; source++) {
      if (source != my_rank) {
         MPI_Recv(char_buffer, BUFSIZ, MPI_CHAR, source, 2002,
                  MPI_COMM_WORLD, &status);
         printf ("%s\n", char_buffer);
      }
   }
}