How to group rows or columns in C++.NET

/*--------------------------------------------------------------------------------
 | Tutorial 17
 |
 | This tutorial shows how to create an Excel file with groups on rows in C++.NET.
 | The Excel file has two worksheets. The first one is full with data and contains
 | the data groups.
 ---------------------------------------------------------------------------------*/

#include <conio.h>
#include <stdio.h>

using namespace System;
using namespace EasyXLS;
using namespace EasyXLS::Constants;

int main()
{
    Console::WriteLine("Tutorial 17\n----------\n");

    // Create an instance of the class that exports Excel files having two sheets
    ExcelDocument ^workbook = gcnew ExcelDocument(2);

    // Set the sheet names
    workbook->easy_getSheetAt(0)->setSheetName("First tab");
    workbook->easy_getSheetAt(1)->setSheetName("Second tab");

    // Get the table of data for the first worksheet
    ExcelWorksheet ^xlsFirstTab = safe_cast<ExcelWorksheet^>(workbook->easy_getSheetAt(0));
    ExcelTable ^xlsFirstTable = xlsFirstTab->easy_getExcelTable();

    // Add data in cells for report header
    for (int column=0; column<5; column++)
    {
        xlsFirstTable->easy_getCell(0,column)->setValue(String::Concat("Column ",(column + 1).ToString()));
        xlsFirstTable->easy_getCell(0,column)->setDataType(DataType::STRING);
    }
    xlsFirstTable->easy_getRowAt(0)->setHeight(30);

    // Add data in cells for report values
    for (int row=0; row<25; row++)
    {
        for (int column=0; column<5; column++)
        {
            xlsFirstTable->easy_getCell(row+1,column)->setValue(
                String::Concat("Data ", (row + 1).ToString(), ", ", (column + 1).ToString()));
            xlsFirstTable->easy_getCell(row+1,column)->setDataType(DataType::STRING);
        }
    }

    // Set column widths
    xlsFirstTable->setColumnWidth(0, 70);
    xlsFirstTable->setColumnWidth(1, 100);
    xlsFirstTable->setColumnWidth(2, 70);
    xlsFirstTable->setColumnWidth(3, 100);
    xlsFirstTable->setColumnWidth(4, 70);

    // Group rows and format A1:E26 cell range
    ExcelDataGroup ^xlsFirstDataGroup = gcnew ExcelDataGroup("A1:E26", DataGroup::GROUP_BY_ROWS, false);
    xlsFirstDataGroup->setAutoFormat(gcnew ExcelAutoFormat(Styles::AUTOFORMAT_EASYXLS1));
    xlsFirstTab->easy_addDataGroup(xlsFirstDataGroup );

    // Group rows and format A2:E10 cell range, outline level two, inside previous group
    ExcelDataGroup ^xlsSecondDataGroup = gcnew ExcelDataGroup("A2:E10", DataGroup::GROUP_BY_ROWS, false);
    xlsSecondDataGroup->setAutoFormat(gcnew ExcelAutoFormat(Styles::AUTOFORMAT_EASYXLS2)); 
    xlsFirstTab->easy_addDataGroup(xlsSecondDataGroup);

    // Export Excel file
    Console::WriteLine("Writing file C:\\Samples\\Tutorial17 - group data in Excel.xlsx.");
    workbook->easy_WriteXLSXFile("C:\\Samples\\Tutorial17 - group data in Excel.xlsx");

    // Confirm export of Excel file
    String ^sError = workbook->easy_getError();
    if (sError->Equals(""))
        Console::Write("\nFile successfully created. Press Enter to Exit...");
    else
        Console::Write(String::Concat("\nError encountered: ", sError, "\nPress Enter to Exit..."));

    // Dispose memory
    delete workbook;

    Console::ReadLine();

    return 0;
}