helloworld.c

#include <mpi.h>
#include <stdio.h>
 
int main(int argc, char *argv[])
{
int rank, nprocs, len;
char   pname[MPI_MAX_PROCESSOR_NAME];


    MPI_Init();       //Work for you
    MPI_Comm_size();  //Work for you
    MPI_Comm_rank();  //Work for you


    MPI_Get_processor_name(); //Work for you
    printf("Hello world! from rank %d of %d on host %s\n", rank, nprocs,pname);


    MPI_Finalize();

    return 0;
}