lab2.1

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

using namespace std;

int main(int argc, char** argv)
{
    int myid, n = 2, *rbuf = 0, *sbuf = 0 ;
    int size;
    MPI_Comm comm = MPI_COMM_WORLD;
    MPI_Init(&argc, &argv);
    MPI_Comm_size(comm, &size);
    MPI_Comm_rank(comm, &myid);

    sbuf = new int [size * n];
    rbuf = new int [size * n];

    for(int i = 0; i < size * n; i++)
    {
        sbuf[i] = myid;
    }
    cout << "Process " << myid << " | ";

    for(int i = 0; i < size * n; i++)
        cout << "  " << sbuf[i];

    MPI_Alltoall(sbuf, n, MPI_INT, rbuf, n, MPI_INT, comm);

    cout << "       " << "Process " << myid << " | ";
    for(int i = 0; i < size * n; i++)
        cout << "  " << rbuf[i];
    cout << endl;

    MPI_Finalize();
}