hat calls the C++ functions from Ruby.

<h2>Key points</h2>

<ul>
<li>To create a new object, you call a constructor like this:

<blockquote>
<pre>
c = Example::Circle.new(10)
</pre>
</blockquote>

<p>
<li>To access member data, a pair of accessor methods are used.
For example:

<blockquote>
<pre>
c.x = 15    # Set member data
x = c.x     # Get member data
</pre>
</blockquote>

<p>
<li>To invoke a member function, you simply do this

<blockquote>
<pre>
print "The area is ", c.area, "\n"
</pre>
</blockquote>