
   the routine <a href="vhat_c.html">vhat_c</a>. 
 </PRE>
<h4><a name="Examples">Examples</a></h4>
<PRE>
 
 
   1) Compute an upward normal of an equilateral triangle lying 
      in the X-Y plane and centered at the origin. 
 
      Example code begins here. 
 
         #include &lt;stdio.h&gt;
         #include &lt;math.h&gt;
         #include &quot;SpiceUsr.h&quot;

         int main()
         {
            ./
            Local variables 
            ./ 
            SpiceDouble             normal[3];
 