void work_on_columns_ex1(void)
{
	Worksheet wksSource, wksResult;
	wksSource = Project.ActiveLayer();
	
	if(!wksSource)
		return;
	
	// Create a result Worksheet
	wksResult.Create();
	
	if(!wksResult)
		return;
	
	Column col;
	int nC, nC1, nC2,
		nR, nR1, nR2,
		nDestC1,
		nNumCols,
		nPos = 0,
		nValue;
		
	double dValue;
	
	string	strName	= "",
			strValue = "",
			strColNameCreated = "";
			
	vector<int>		naFourthColumn;
	vector<double>	daFifthColumn;
	
	bool bRet;
	int  nRet;
	
	for(int i = 3; i < wksSource.Columns.Count(); i+=5)
	{		
		nR = 0;
		nC = i; // 4., 8., 12. column ...
		bRet = wksSource.GetCell( nR, nC, strValue );
		if( bRet )
		{
			dValue = atof( strValue );	// Convert the String value to Integer
			nValue = nint( dValue );	// next integer to double value
		}
		// Store integer Values in vector
		naFourthColumn.Add(nValue);
	}
	
	for(int ii = 4; ii < wksSource.Columns.Count(); ii+=5)
	{
		nR = 0;
		nC = ii; // 5., 10., 15. column ...
		
		bRet = wksSource.GetCell( nR, nC, strValue );
		if( bRet )
		{
			dValue = atof( strValue ) // Convert the String value to Double;
		}
		// Store double Values in vector
		daFifthColumn.Add(dValue);
	}

	// copy first column to result Worksheet
	col = wksSource.Columns(0);
	nC1 = col.GetIndex();
	nC2 = col.GetIndex();
	nR1 = 0;
	nR2 = col.GetNumRows();
	nDestC1 = 0;
	DWORD dwCtrl = CPYT_COPY_COLUMN_FORMAT | CPYT_COPY_COLUMN_DESIGNATIONS;
	
	nRet = wksSource.CopyTo(wksResult, nC1, nC2, nR1, nR2, nDestC1, -1, dwCtrl); 
	
	// copy rest of relevant columns to result Worksheet
	for(int j = 0; j < wksSource.Columns.Count(); j+=5)
	{
		col = wksSource.Columns(j+1); // 2., 7., 12. column ...
		nC1 = col.GetIndex();
		nC2 = col.GetIndex();
		nR1 = 0;
		nR2 = col.GetNumRows();
		nDestC1++;
		DWORD dwCtrl = CPYT_COPY_COLUMN_FORMAT | CPYT_COPY_COLUMN_DESIGNATIONS;
		
		nRet = wksSource.CopyTo(wksResult, nC1, nC2, nR1, nR2, nDestC1, -1, dwCtrl); 
	}
	
	// change column names
	nNumCols = wksResult.Columns.Count();
	for(int k = 1; k < nNumCols; k++)
	{		
		// If value of fifth column is negativ append an 'n'
		if( daFifthColumn[k-1] < 0.)
			strName.Format("%dn", naFourthColumn[k-1]);
		else
			strName.Format("%d", naFourthColumn[k-1]);
		
		col = wksResult.Columns(k);
		col.SetName(strName);
	}
	
	string strLT_command;
	int nColResult, nColSource1, nColSource2;

	// Add new result columns
	nNumCols = wksResult.Columns.Count();
	for(int kk = 0; kk < (nNumCols-1); kk+=2)
	{
		nPos += 3;
		string strColNameCreated;

		strName.Format("n%d", naFourthColumn[kk]);
		wksResult.InsertCol( nPos, strName, strColNameCreated );
		
		Collection<Column> cCol;
		cCol = wksResult.Columns;
		
		col = cCol.Item(strColNameCreated);
		nColResult	= col.GetIndex() + 1;
		nColSource1	= nColResult - 2;
		nColSource2	= nColResult - 1;
		
		// Execute a Labtalk statement to operate on the columns
		strLT_command.Format("col(%d) = 1000/1.6*4/(col(%d)-col(%d))", nColResult, nColSource1, nColSource2);
		LT_execute( strLT_command );
	}
}