#include <stdio.h>
#include <mpi.h>
#include <string.h>   // strcpy MPI_CHAR

const int tag = 10;

int main(int argc, char **argv)
{
  int pid, nprocs;
  MPI_Init(&argc, &argv);
  MPI_Comm_rank(MPI_COMM_WORLD, &pid);
  MPI_Comm_size(MPI_COMM_WORLD, &nprocs);

  int a = pid;
    //echange simple point à point
    if(pid==0)
        MPI_Send(&a,1,MPI_INT,1,tag,MPI_COMM_WORLD);
    if(pid==1)
        MPI_Recv(&a,1,MPI_INT,0,tag,MPI_COMM_WORLD,MPI_STATUS_IGNORE);
   
    
    printf("Je suis processus %d a= %d", pid,a);
   // Je suis processus 1 a= 0
   // Je suis processus 1 a= 0
    
    
    // np 4
    
    char msg[];

    if(pid==0)
    {
        strcpy(msg,"hello from 0");
    }
    MPI_Bcast(&msg,sizeof(msg),MPI_CHAR,0,MPI_COMM_WORLD);
    printf("Je suis processus %d le message = %s", pid,msg);
    
    Je suis processus 0 le message = hello from 0
    Je suis processus 2 le message  = hello from 0
    Je suis processus 1 le message = hello from 0
    Je suis processus 3 le message = hello from 0
   int Tab[10],i;
   
    char msg[20];
  if (pid == 0)
      strcpy(msg,"bonjour");
    

 MPI_Bcast(&msg, sizeof(msg), MPI_CHAR, 0 , MPI_COMM_WORLD);
    
 printf ("processus %d msg = %s\n", pid,msg);
    
    
  PO,P1,P2,P3
    int a=23;
    if(pid==0) // root
    {
        a=367;
        MPI_Send(&a,1,MPI_INT,1,12,MPI_COMM_WORLD);
        MPI_Send(&a,1,MPI_INT,2,12,MPI_COMM_WORLD);
        MPI_Send(&a,1,MPI_INT,3,12,MPI_COMM_WORLD);
        MPI_Send(&a,1,MPI_INT,0,12,MPI_COMM_WORLD);
        MPI_Recv(&a,1,MPI_INT,0,12,MPI_COMM_WORLD,MPI_STATUS_IGNORE);
    }
    else{
      //  int c;
        MPI_Recv(&a,1,MPI_INT,1,12,MPI_COMM_WORLD,MPI_STATUS_IGNORE);
        MPI_Recv(&a,1,MPI_INT,2,12,MPI_COMM_WORLD,MPI_STATUS_IGNORE);
        MPI_Recv(&a,1,MPI_INT,3,12,MPI_COMM_WORLD,MPI_STATUS_IGNORE);
    }
    
    
    
    int a=23;
    if(pid==2) // root
    {
        a=367;
       
    }
    MPI_Bcast(&a, 1, MPI_INT, 2 , MPI_COMM_WORLD);

    
 
    
    printf("le processus %d a la valeur a=%d",pid,a);
    
    
    
    
   //MPI_Send(&a, 1, MPI_INT, 1, tag, MPI_COMM_WORLD);
  //if (pid == 1)
   // MPI_Recv(&a, 1, MPI_INT, 0, tag, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
 // 1. MPI_Bcast(msg, 1, MPI_INT, 0 , MPI_COMM_WORLD);
  //printf("%s je suis %d\n",msg, pid);
  //Q2
    
    
    
if(pid==0)
{
    for (i=0;i<10;i++)
        Tab[i] = i;
    
}
MPI_Bcast(Tab,10, MPI_INT,0, MPI_COMM_WORLD);
	
  for (i=0;i<10;i++) printf("Processus %d ---> tab[%d]=%d\n", pid, i,Tab[i]);

  MPI_Finalize();
  return 0;
}