Problem in Code

Can anyone tell what this code is doing:

protected void btnExport_Click(object sender, EventArgs e)
{
    // Get the report document
    ReportDocument repDoc = getReportDocument();
    // Stop buffering the response
    Response.Buffer = false;
    // Clear the response content and headers
    Response.ClearContent();
    Response.ClearHeaders();
    try
    {
        // Export the Report to Response stream in PDF format and file name Customers
        repDoc.ExportToHttpResponse(ExportFormatType.PortableDocFormat,Response,true,"Customers");
        // There are other format options available such as Word, Excel, CVS, and HTML in the ExportFormatType Enum given by crystal reports
    }
    catch(Exception ex)
    {
        Console.WriteLine(ex.Message);
        ex = null;
    }