root

void graph() {
   TCanvas *c1 = new TCanvas("c1","Testing",200,10,500,500);
   c1->SetFillColor(50);
   c1->SetGrid();
   const Int_t n = 50;
   Double_t x[n], y[n];
   for (Int_t i=0;i<n;i++) {
     x[i] = i;
     y[i] = x[i]*x[i];
   }
   gr = new TGraph(n,x,y);
   gr->SetLineColor(2);
   gr->SetLineWidth(5);
   gr->SetMarkerColor(5);
   gr->SetMarkerStyle(20);
   gr->SetTitle("Testing");
   gr->GetXaxis()->SetTitle("X axis");
   gr->GetYaxis()->SetTitle("Y axis");
   gr->Draw("ACP");
}