In reply to sraja:
Can you write your description in the form:
If (this_condition_happens) then (this condition must happen)
If (this_condition_happens) then (this condition must not happen)
In reply to sraja:
Can you write your description in the form:
If (this_condition_happens) then (this condition must happen)
If (this_condition_happens) then (this condition must not happen)