A simple program
Preprocessor directive
This line is read "pound
include i-o-stream dot h".
The effect of this line is to
essentially "copy and
paste" the entire file
iostream.h into your own
file at this line. So you can
think of this syntax as
replacing the line #include
<iostream.h> with the
contents of the file
iostream.h. #include is
known as a preprocessor
directive.
//include this file for cout
#include <iostream.h>
int main()
{
   //print out the text string,
   //"Hello, World!"
   cout << "Hello, World!"
       << endl;
   return 0;
}