The number one program is Hello World.
This program prints the string "Hello World".
iostream is part of the standard library that comes with
C++, iostream deals with input, output streams.
cout belongs to namespace std, it's full name is std::cout
we can shorten this to cout by using the namespace.
The method main is the one that
gets run.
cout represents the standard
(console) output. The operator << takes an
output stream on the left
value to be output on the right.