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

int main ( int argc, char *argv[] )
{
  int ierr;
  int num_procs;
  int my_id;

  ierr = MPI_Init ( &argc, &argv );
  ierr = MPI_Comm_rank ( MPI_COMM_WORLD, &my_id );
  if ( my_id == 0 ) 
  {
    ierr = MPI_Comm_size ( MPI_COMM_WORLD, &num_procs );
    printf ( "\n" );
    printf ( "HELLO_WORLD - Master process:\n" );
    printf ( "  A simple C program using MPI.\n" );
    printf ( "\n" );
    printf ( "  The number of processes is %d.\n", num_procs );
    printf ( "\n" );
  }
  else
  {
    printf ( "  Process %d says 'Hello, world!'\n", my_id );
  }
  ierr = MPI_Finalize ( );
  return 0;
}