main.cpp

#include <iostream>
#include <cstdio>
#include <cstddef>
#include <vector>
#include <mpi.h>

using namespace std;

class Car {
public:
	int shifts;
	int topSpeed;
	double pos[3];
};


int main(int argc, char* argv[]) {
    const int tag = 13;
    int size, rank;

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

    if (size < 2) {
        fprintf(stderr,"Requires at least two processes.\n");
    }

    /* create a type for struct car */
    const int nitems = 3;
    int          blocklengths[3] = {1, 1, 3};
    MPI_Datatype types[3] = {MPI_INT, MPI_INT, MPI_DOUBLE};
    MPI_Datatype mpi_car_type;
    MPI_Aint     offsets[3];

    offsets[0] = offsetof(Car, shifts);
    offsets[1] = offsetof(Car, topSpeed);
    offsets[2] = offsetof(Car, pos);

    MPI_Type_create_struct(nitems, blocklengths, offsets, types, &mpi_car_type);
    MPI_Type_commit(&mpi_car_type);

    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    if (rank == 0) {
        vector<Car> send;

        send.push_back(Car());
        send.push_back(Car());
        send[0].shifts = 4;
        send[0].topSpeed = 100;
        send[0].pos[0] = 0.5;
        send[0].pos[1] = 0.6;
        send[0].pos[2] = 0.7;

        send[1].shifts = 5;
        send[1].topSpeed = 200;
        send[1].pos[0] = 1.5;
        send[1].pos[1] = 1.6;
        send[1].pos[2] = 1.7;

        const int dest = 1;
        MPI_Send(&send[0],   2, mpi_car_type, dest, tag, MPI_COMM_WORLD);
        printf("Rank %d: sent structure car\n", rank);
    }
    if (rank == 1) {
        MPI_Status status;
        const int src=0;

        vector<Car> recv;

        recv.reserve(2);
        MPI_Recv(&recv[0],   2, mpi_car_type, src, tag, MPI_COMM_WORLD, &status);
        printf("Rank %d: Received: shifts = %d topSpeed = %d | %f | %f | %f\n", rank,
                 recv[0].shifts, recv[0].topSpeed, recv[0].pos[0], recv[0].pos[1], recv[0].pos[2]);
        printf("Rank %d: Received: shifts = %d topSpeed = %d | %f | %f | %f\n", rank,
                 recv[1].shifts, recv[1].topSpeed, recv[1].pos[0], recv[1].pos[1], recv[1].pos[2]);

    }

    MPI_Type_free(&mpi_car_type);
    MPI_Finalize();
	return 0;
}