q1.c

// A group is an ordered set of process identifiers (rank)
// A communicator encapsulates all communication among a set of processes i.e the group.
// https://www.clustermonkey.net/MPI/mpi-groups-and-communicators.html
#include <stdio.h>
#include <mpi.h>

int main (int argc, char *argv[]) {
    //Declare int variables for Process number, number of processes and length of processor name.
    int rank, size, namelen;
    
    //Declare char variable for name of processor 
    char name[100];
    
    //Intialize MPI 
    MPI_Init(&argc, &argv);
    
    //Get number of processes 
    MPI_Comm_size(MPI_COMM_WORLD, &size);
    
    //Get processes number 
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    
    //Get processesor name 
    MPI_Get_processor_name(name, &namelen);
    
    printf ("Hello World. Rank %d out of %d running on %s!\n", rank, size, name);
    
    //Terminate MPI environment 
    MPI_Finalize(); 
    return 0; 
}