The method MakeValidRowRange ensures that the matrix row indexes LowRow and HighRow are within the valid index range of the matrix (i.e. they are greater or equal to 1 and less than or equal to NrOfRows). If any of the two variable parameters falls outside the valid range, it is adjusted to the nearest limit. Passing a zero value to both parameters returns the minimum and maximum range values (i.e. 1 and NrOfRows).
The function returns the following codes:
0 ... both LowRow and HighRow are within the valid range, no adjustments made
1 ... LowRow and/or HighRow have been adjusted because they were outside the valid range
