My solution to: http://www.hpc.cineca.it/content/exercise-1-0

ex1.c

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

int main (int argc, char** argv) {
    int rank, size;

    MPI_Init(&argc, &argv);
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    MPI_Comm_size(MPI_COMM_WORLD, &size);

    printf("Hello world, I am proc %d of total %d\n", rank, size);

    MPI_Finalize();
    return 0;
}