I am trying to create a ROOT file with the histogram I generated. However, when I view the histogram from the file, there is a legend missing. Can you please tell how can I fix this? Thank you.
void histo()
4 {
5 Int_t nBins = 120000; //Bin Size = 0.001 GeV
6 Int_t x_lo = 0;
7 Int_t x_hi = 120;
8
9 //Stacking Histogram with THStack
10 THStack *histos = new THStack("histos", "Stacked Neutrino Histograms for Target Radius 1 cm; Energy [GeV]; Entries/0.001 GeV");
11 TH1D* hist1 = new TH1D("nu_e_Hist", "Histogram Title", nBins, x_lo, x_hi);
12 hist1->SetMarkerStyle(20);
13 hist1->SetLineColor(kRed);
14
15 TH1D* hist2 = new TH1D("nu_mu_Hist", "Histogram Title", nBins, x_lo, x_hi);
16 hist2->SetMarkerStyle(21);
17 hist2->SetLineColor(kBlue);
18
19 TH1D* hist3 = new TH1D("anti_nu_e_Hist", "Histogram Title", nBins, x_lo, x_hi);
20 hist3->SetMarkerStyle(22);
21 hist3->SetLineColor(kGreen-3);
22
23 TH1D* hist4 = new TH1D("anti_nu_mu_Hist", "Histogram Title", nBins, x_lo, x_hi);
24 hist4->SetMarkerStyle(23);
25 hist4->SetLineColor(kBlack);
26
27 histos->Add(hist1);
28 histos->Add(hist2);
29 histos->Add(hist3);
30 histos->Add(hist4);
31
32 //Working with ROOT File
33 TFile* fInput = new TFile("TargetVStudy_1cm_POT1000.root", "READ"); //READ
34 TTree* tree = (TTree*)fInput->Get("DUNETargetSim");
35
36 Char_t pid[32]; //Particle Identification
37 Double_t Energy; //Kinetic Energy
38
39 tree->SetBranchAddress("pid", &pid);
40 tree->SetBranchAddress("kineticEnergy", &Energy);
41
42 //Looping over to get the data for specific particle and filling the selected histogram
43 Int_t nEntries = tree->GetEntries("kineticEnergy");
44 for (Int_t i = 0; i < nEntries; i++)
{
46 tree->GetEntry(i);
47
48 for (Int_t j = 0; j < 4; j++)
49 {
50 switch(j) {
51 case 0:
52 if(strcmp(pid, "nu_e") == 0) { hist1->Fill(Energy); }
53 break;
54 case 1:
55 if(strcmp(pid, "nu_mu") == 0) { hist2->Fill(Energy); }
56 break;
57 case 2:
58 if(strcmp(pid, "anti_nu_e") == 0) { hist3->Fill(Energy); }
59 break;
60 case 3:
61 if(strcmp(pid, "anti_nu_mu") == 0) { hist4->Fill(Energy); }
62 break;
63 default:
64 // cout << "Hey There!" << endl;
65 ;
66
67 }
68 }
69 }
70
71 TCanvas* c1 = new TCanvas();
72 c1->SetTicks();
73 c1->SetGrid();
74 c1->SetLogy();
75 histos->Draw("nostack");
76
77 //Drawing Legend
78 TLegend *leg = new TLegend();
79 leg->SetHeader("#nu types", "C"); //C means center
80 leg->AddEntry(hist1, "nu_e", "f"); //f gives a square box
81 leg->AddEntry(hist2, "nu_mu", "f");
82 leg->AddEntry(hist3, "anti_nu_e", "f");
83 leg->AddEntry(hist4, "anti_nu_mu", "f");
84 leg->Draw();
85
86 TFile* output = new TFile("all_nu_stacked_1cm.root", "RECREATE");
87 histos->Write();
88 output->Close();
89 }
