/* MCS 572 Wed 18 Jan 2012 : broadcast_integer.c
 * The code illustrates the manager/worker paradigm with a broadcast.
 * To compile, type: "mpicc broadcast_integer.c -o broadcast_integer";
 * to run on 4 processors, type: "mpirun -np 4 broadcast_integer". */

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

void manager ( int* n );
/* code executed by the manager node 0,
 * prompts the user for an integer number n */

void worker ( int i, int n );
/* code executed by the i-th worker node,
 * who will write the integer number n to screen */

int main ( int argc, char *argv[] )
{
   int myid,numbprocs,n;

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

   if (myid == 0) manager(&n);
      
   MPI_Bcast(&n,1,MPI_INT,0,MPI_COMM_WORLD);

   if (myid != 0) worker(myid,n);

   MPI_Finalize();

   return 0;
}

void manager ( int* n )
{
   printf("Type an integer number... \n");
   scanf("%d",n);
}

void worker ( int i, int n )
{
   printf("Node %d writes the number n = %d.\n",i,n);
}