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

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

    /* initialize MPI */
    MPI_Init(&argc, &argv);

    /* get the rank (process rank) and size (number of processes) */
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    MPI_Comm_size(MPI_COMM_WORLD, &size);

    /* we start to work */
    printf("Process %d starting!\n", rank);

    /* simulate the processes taking slightly different amounts of time by sleeping
     * for our process rank seconds */
    sleep(rank);
    printf("Process %d is done its work!\n", rank);
    fflush(stdout);

    /* a barrier */
    MPI_Barrier(MPI_COMM_WORLD);

    printf("Process %d is past the barrier!\n", rank); 
    fflush(stdout);

    /* quit MPI */
    MPI_Finalize();
    return 0;
}