To begin developing in C++ create an empty
document with a cpp file extension and open
it in the editor of your choice. In my case
I'll be using Visual Studio and have included
the file in an new empty project. If you don't
have Visual Studio but would like to follow
along in a similar environment you can download
Visual C++ Express from Microsoft's website.
This is one of several free version of this
program.
The first thing we'll add to the source file
is the main method. This is the entry point
of the program and the code inside the braces
is what will be executed when the program
runs.
Our first application will simply output the
text "Hello World" to the screen. Before we
can do that however we need to include the
iostream header. This header provides input
and output functionality for our program and
is one of the standard libraries that comes
with all compilers. What the include directive
does is effectively to replace the line with
everything in the specified header before
the file is compiled into an executable.
If we're wondering what the header file contains
we can take a look at it by right clicking
on its name and selecting "open document".
Among other things we can here find out the
exact location of the header. With IOStream
now included we gain access to several new
functions. These are all located in the standard
namespace called "std" which we can go inside
using a double colon, also called the scope
operator.
In Visual Studio the IntelliSense window will
now automatically show up displaying what
the namespace contains. Among the members
we here find the "cout" stream which is the
standard output stream in C++ that we can
use to print text to a console window. It
uses two less-than signs (<<) known as the
insertion operator to indicate what to output.
We can now write our string here delimited
by double quotes. After the statement we place
a semicolon, which is used in C++ to mark
the end of all expression statements.
If we want to make things a bit easier we
can add a line specifying that we're using
the standard namespace (std). We then no longer
have to prefix cout with the namespace since
it's now used by default.
