mpi_pingpong

#include <stdio.h>
#include <string.h>
#include <mpi.h>
#define size 20

int main (int argc, char **argv)
{
    char message[size] = {};
    int myrank;

    MPI_Status status;
    MPI_Init (&argc, &argv);
    MPI_Comm_rank (MPI_COMM_WORLD, &myrank);

    if (myrank == 0)
    {
        strcpy (message, "Hi, process one\n");
        MPI_Send(message, strlen(message), MPI_CHAR, 1, 99, MPI_COMM_WORLD);
        printf("I'm process 0. Sent message to 1\n");

        MPI_Recv(message, size, MPI_CHAR, 1, 99, MPI_COMM_WORLD, &status);
        printf("I'm process 0. Received message from 1\n");
    }
    else
    {
        MPI_Recv (message, size, MPI_CHAR, 0, 99, MPI_COMM_WORLD, &status);
        printf("I'm process 1. Received message from 0\n");

        MPI_Send(message, strlen(message), MPI_CHAR, 0, 99, MPI_COMM_WORLD);
        printf("I'm process 1. Sent message to 0\n");
    }

    MPI_Finalize();

    return 0;
}