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

main(int argc, char **argv)
{
 int my_rank;
 int p;
 int source;
 int dest;
 int tag=50;
 char message[100];
 MPI_Status status;

 MPI_Init(&argc,&argv);
 MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);
 MPI_Comm_size(MPI_COMM_WORLD, &p);
 if (my_rank == 1) {
   printf("I'm number 1!\n");
   sprintf(message,"Hello from %d!", my_rank);
   dest=0;
   MPI_Send(message,strlen(message)+1, MPI_CHAR, dest, tag, MPI_COMM_WORLD);

 }
 else if (my_rank !=0) {
   sprintf(message,"Greetings from %d!", my_rank);
   dest=0;
   MPI_Send(message,strlen(message)+1, MPI_CHAR, dest, tag, MPI_COMM_WORLD);
 }
 else {
   for (source =1; source <p; source++)
   {
     MPI_Recv(message, 100, MPI_CHAR, source, tag, MPI_COMM_WORLD,&status);
     printf("%s\n",message);
   }
 }
 MPI_Finalize();
 return 0;
}