
Exercise 'master-worker'
~~~~~~~~~~~~~~~~~~~~~~~~

Write a simple master-worker program.

No real work has to be performed.  Work is emulated by waiting for one
second.  This can be implemented with the following system calls:

	C       : #include <stdlib.h>
        	  system("sleep 1");
 
	Fortran : call system("sleep 1")   ! (ifort and gfortran compilers)

The master's task is to send task IDs to the workers upon their request.
(Task IDs are integers from 1 to MAXTASK=40, say.)

If the task queue is empty the master sends an 'end-of-work' message.
(The master can send -1 as a task ID, for example.) 

The workers are supposed to print out their rank and the task ID they received
and then wait for one second.

Hint: Read about 'MPI_ANY_SOURCE' in the MPI standard and the 'status'
returned in MPI_Recv().
