Example 3.  Writing a Vdata of Homogeneous Type

This example illustrates the use of VSfdefine/vsffdef, VSsetname/vsfsnam,
VSsetclass/vsfscls, VSsetfields/vsfsfld, and VSwrite/vsfwrt to create and
write a three-field vdata to the file "General_Vdatas.hdf". Although the
fields have data of the same type, they have different orders.

To clarify the illustration, let us assume that the vdata is used to
contain the data of some particles collected from an experiment.
Each record of the data includes the position of a particle, its weight,
and the minimum and maximum temperature the particle can endure.  The
vdata is named "Solid Particle", contains 10 records, and belongs to a
class, named "Particle Data".  The fields of the vdata include
"Position", "Mass", and "Temperature".  The field "Position" has an order
of 3 for the x, y, and z values representing the position of a particle.
The field "Mass" has an order of 1.  The field "Temperature" has an order of
2 for the minimum and maximum temperature.  The program creates the
vdata, sets its name and class name, defines its fields, and then
writes the data to it.