Bash

A simple hello world example using Bash.

HelloWorld.sh:

#!bin/sh

echo "Hello world!"

To run it:

$ chmod +x HelloWorld.sh
$ ./HelloWorld.sh

C

C with MPI

#include <stdio.h>
#include <mpi.h>


int main (argc, argv)
     int argc;
     char *argv[];
{
  int rank, size;

  MPI_Init (&argc, &argv);	/* starts MPI */
  MPI_Comm_rank (MPI_COMM_WORLD, &rank);	/* get current process id */
  MPI_Comm_size (MPI_COMM_WORLD, &size);	/* get number of processes */
  printf( "Hello world from process %d of %d\n", rank, size );
  MPI_Finalize();
  return 0;
}
</source>

And to compile:

<source lang="bash">
$ mpicc hello.c -o hello.o

$ mpirun -np 4 ./hello.o # or whatever your MPI's command line cup of tea is

C++

A simple hello world example in C++.

HelloWorld.cc:

#include <iostream>
 
int main()
{
     std::cout << "Hello, world! This is C++.\n";
}

To run it:

$ g++ HelloWorld.cc -o hello.x
$ ./hello.x

C++ with MPI

A simple hello world example in C++ with MPI:

#include <iostream>
#include <cstdlib>		// has exit(), etc.
#include <mpi++.h>		// MPI header file

int main(int argc, char *argv[]) {

  // initialize for MPI (should come before any other calls to
  //     MPI routines)
  MPI::Init(argc, argv);

  // get number of processes
  int nprocs = MPI::COMM_WORLD.Get_size();

  // get this process's number (ranges from 0 to nprocs - 1)
  int myid = MPI::COMM_WORLD.Get_rank();

  // print a greeting
  cout << "hello from process " << myid << " of " << nprocs << endl;

  // clean up for MPI 
  MPI::Finalize();

  return EXIT_SUCCESS;
}

To compile and run it:

$ mpic++ hello.cpp -o hello.o

$ mpirun -np 4 ./hello.o

http://www.cs.trinity.edu/~bmassing/Classes/CS3366_2002spring/SamplePrograms/index.html

PHP

A simple hello world example using PHP.

HelloWorld.php:

<html>
<body>
<?php
echo "Hello world!";
?>
</body>
</html>

To run HelloWorld.php:

$ php HelloWorld.php

Alternatively, if you are running a local apache server and have PHP enabled, you can put HelloWorld.php into your web documents directory, and then point you web browser to http://localhost/HelloWorld.php.

If you need help understanding how to do that, check out my page on building and running Apache. If you need help translating that into human-speak, Lifehacker has a really great article explaining how to set up a web server on your machine.

Python

A simple hello world example using Python.

HelloWorld.py:

 print "Hello, World!"

To run it:

$ python HelloWorld.py

Alternatively:

$ python -c "print 'Hello World! \n'"

Hello World

From charlesreid1

Contents

Bash

C

C with MPI

C++

C++ with MPI

PHP

Python