How to save the data showed into a TGraph

I’m developing a standalone application compiled with gcc.
How is possible to save into a simple text file the data showed into a TGraph?
Thank yoy very much
Best regards
Andrea Bulgarelli

Use TGraph::Print or TCanvas::SaveAs


But with Print of Save every thing of the Canvas is saved (for example in XML that contains the data in a readable ascii format), but I need only to save the numeric value of the graphs into an ascii file.
Thank you
Andera Bulgarelli