/*
** $Id: hello.cc 824 2008-03-09 19:23:52Z phf $
*/

// The iostream include allows access to the standard
// input/output/error streams, similar to stdio.h for
// regular C programming.

#include <iostream>

int main()
{
  // The "std" namespace refers to elements of the
  // standard library. If we'd put
  //
  //   using namespace std;
  //
  // or (slightly better)
  //
  //   using std::cout;
  //   using std::endl;
  //
  // before main(), we could write
  //
  //   cout << "Hello World!" << endl;
  //
  // instead of what we write here. However, we did
  // discuss why this "using" stuff is a bad idea.

  std::cout << "Hello World!" << std::endl;

  // The "<<" operator refers to an overloaded method;
  // overloaded versions exist for strings, ints, and
  // all kinds of other "standard" types which can all
  // be printed this way. Writing several "<<" next to
  // each other works because "<<" returns the stream
  // that it modifies. In other words, the line above
  // evaluates as
  //
  //   (std::cout << "Hello World!") << std::endl;
  //   (std::cout << std::endl);
  //   (std::cout);
  //
  // and finally the value is ignored, but not before
  // the two parts were written to the standard output.
  // We can see this more clearly as follows: First,
  // we could have written the same output using two
  // instructions:

  std::cout << "Hello World!";
  std::cout << std::endl;

  // Second, if we evaluate std::cout by itself, nothing
  // whatsoever happens on the output.

  std::cout; // we'll get a warning about "no effect" here

  // If we don't put a return here, the compiler will
  // add a "return 0;" by default indicating that the
  // program worked "okay" to the shell.
  return 0;
}