This example shows how to use Geant4 as a generator for simulating
inelastic hadron-nuclear interactions.

The class HadronicGenerator is the "generator".
The main hadronic models (FTFP, QGSP, BERT, BIC, IonBIC, INCL)
and some combinations of two of them - in a transition energy region,
similarly to what happens in physics lists - are available.
See include/HadronicGenerator.hh for more detailed information.

The main, Hadr09.cc, shows an example of how to use it.
It samples randomly the projectile hadron, its energy, its direction
and the target material, and then it calls the generator.
Some information regarding the secondaries which are produced can be
printed out.
See the comments in Hadr09.cc for more information and how eventually
to change some of its configurations.
Notice that Hadr09.cc does nothing really useful: users should consider
to use eventually only the class HadronicGenerator.

(
  The file Hadr09.cc-ION_PROJECTILE shows an example of a ion-ion
  collision, for fixed type of projectile ion, target ion, projectile
  kinetic energy, and projectile direction.
  This file is obtained from Hadr09.cc with minimal changes.
)

Notice that the Geant4 run-manager is not used.

To build this example:
  mkdir Build; cd Build
  cmake -DCMAKE_BUILD_TYPE=RelWithDebInfo \
        -DGeant4_DIR=/path-to-geant4-libraries ../.
  make

To run it:
  ./Hadr09 [Hadr09.in]
  
which simulates 1000 hadron-nucleus collisions, randomnly selected, and
prints out some information about the secondaries produced in these
interactions. It takes only a few seconds to run.
Notice that the input file, Hadr09.in, which is empty, is not needed
by Hadr09, and can be omitted; however, it has been created because
is expected by system testing.

Note: this example has been included in Geant4 10.7, but it should work
      also for early versions of Geant4, in particular 10.6, 10.5 and 10.4.