# A simple graph with axis titles

    {
       //
       // To see the output of this macro, click  here.
       //
       gROOT->Reset();
       c1 = new TCanvas("c1","A Simple Graph Example",200,10,700,500);

       c1->SetFillColor(42);
       c1->SetGridx();
       c1->SetGridy();

       const Int_t n = 20;
       Float_t x[n], y[n];
       for (Int_t i=0;i<n;i++) {
         x[i] = i*0.1;
         y[i] = 10*sin(x[i]+0.2);
         printf(" i %i %f %f n",i,x[i],y[i]);
       }
       gr = new TGraph(n,x,y);
       gr->SetFillColor(19);
       gr->SetLineColor(2);
       gr->SetLineWidth(4);
       gr->SetMarkerColor(4);
       gr->SetMarkerStyle(21);
       gr->SetTitle("a simple graph");
       gr->Draw("ACP");

       //Add axis titles.
       //A graph is drawn using the services of the TH1F histogram class.
       //The histogram is created by TGraph::Paint.
       //TGraph::Paint is called by TCanvas::Update. This function is called by default
       //when typing <CR> at the keyboard. In a macro, one must force TCanvas::Update.

       c1->Update();
       c1->GetFrame()->SetFillColor(21);
       c1->GetFrame()->SetBorderSize(12);
       gr->GetHistogram()->SetXTitle("X title");
       gr->GetHistogram()->SetYTitle("Y title");
       c1->Modified();
    }