use constant EXPENSE_FILE      => 'expense.dat';
    use constant EXPENSE_REPORT    => 'final_expense.txt';
    use constant FIELDS_PER_RECORD => 4;
    use constant REPORT_HEADER     => "Department,Total\n";
    use constant ERROR_REPORT      => 'expense_error.txt';
    use constant ERROR_HEADER      => "Department,Employee,Total,Description\n";
    use constant EXCESSIVE         => 200;

    my $raw_expenses                 = get_expense_data( EXPENSE_FILE );
    my ( $expenses, $largeExpenses )
        = split_normal_from_excessive( $raw_expenses, EXCESSIVE );
    my $deptTotals = sum_expenses_by_department($expenses, FIELDS_PER_RECORD);
    write_report( $deptTotals, EXPENSE_REPORT, REPORT_HEADER );
    write_report( $large_expenses, ERROR_REPORT, ERROR_HEADER );