Hello world from process i of nusing the rank in MPI_COMM_WORLD for i and the size of MPI_COMM_WORLD for n. You can assume that all processes support output for this example.
Note the order that the output appears in. Depending on your MPI implementation, characters from different lines may be intermixed. A subsequent exercise (I/O master/slaves) will show how to order the output.
You may want to use these MPI routines in your solution:
MPI_Init MPI_Comm_size MPI_Comm_rank MPI_Finalize