//Instantiate a new workbook
Workbook workbook = new Workbook("book1.xls");

//Get the Cells collection in the first worksheet
Cells cells = workbook.getWorksheets().get(0).getCells();

//Create a cellarea i.e.., B3:C19
CellArea ca = new CellArea();
ca.StartRow = 2;
ca.StartColumn =1;
ca.EndRow = 18;
ca.EndColumn = 2;

//Apply subtotal, the consolidation function is Sum and it will applied to
//Second column (C) in the list
cells.subtotal(ca, 0, ConsolidationFunction.SUM, new int[] { 1 });

//Save the excel file
workbook.save("AsposeTotal.xls");