{
c1 = new TCanvas("c1","c1 title", 200, 100, 800, 600);
c1->SetGrid();
//
//
double x1[200], y1[200];
int n1=0;
ifstream fin("higgs_gg_14.txt");
char line[255];
fin.getline(line,sizeof(line)); // skipping the 1st dummy line
while (fin >> x1[n1] >> y1[n1] ) n1++;
cout<<"number of data at 14 TeV = "<<n1<<endl;
fin.close();
//
double x2[200], y2[200];
int n2=0;
ifstream fin("higgs_gg_7.txt");
char line[255];
fin.getline(line,sizeof(line)); // skipping the 1st dummy line
while (fin >> x2[n2] >> y2[n2] ) n2++;
cout<<"number of data at 7 TeV = "<<n2<<endl;
fin.close();
//
g1 = new TGraph(n1, x1, y1);
g2 = new TGraph(n2, x2, y2);
g1->SetLineColor(2);
g2->SetLineColor(4);
g1->SetLineWidth(2);
g2->SetLineWidth(2);
g1->GetXaxis()->SetTitle("m_{H} [GeV]");
g1->GetYaxis()->SetTitle("cross section [pb]");
gPad->SetLogy();
g1 -> Draw("AL");
g2 -> Draw("SAME L");
//
leg = new TLegend(0.6,0.77,0.93,0.9,"pp->H via gluon fusion");
leg->AddEntry(g1,"ECM=14 TeV","l");
leg->AddEntry(g2,"ECM= 7 TeV","l");
leg->SetFillColor(10);
leg->Draw();
//
c1->Print("gluon_fusion.png");
}