#include "TH1.h"
#include "TF1.h"
#include "TLegend.h"
#include "TCanvas.h"
#include "math.h"
TLegend *BuilLegend(TMultiGraph *mg, Double_t x1, Double_t y1, Double_t x2, Double_t y2, char* title, char* names[5]);

void
plot_graph() {

     TCanvas *c1 = new TCanvas("ewb", "ewb",281,93,700,500);
     c1->SetGrid();
     
     Int_t ypoints[13] = {1,1,1,1,1,1,1,1,1,1,1,1,1};
     
     Int_t xpoints[13] = {1,2,3,4,5,6,7,8,9,10,11,12,13};
     
     TGraph *gr1 = new TGraph(13, xpoints, ypoints);
     
     Int_t xpoints1[13] = {1,2,3,4,5,6,7,8,9,10,11,12,13};
     
     Int_t ypoints1[13] = {2,2,2,2,2,2,2,2,2,2,2,2,2};
     
     TGraph *gr2 = new TGraph(13, xpoints1, ypoints1);
     
     TMultiGraph *mgr = new TMultiGraph("mgr", "mgr");     
     
     mgr->Add(gr2);
     mgr->Add(gr1);
     
     TH1 *h1 = mgr->GetHistogram();
     
     h1->Rebin();
     // Get by default returns a TObject, hence we need to typecast it
     
     std::vector<std::string> label;
     
     label.push_back("6.3x10^{-5}");
     label.push_back("1.0x10^{-4}");
     label.push_back("4.7x10^{-4}");
     label.push_back("0.0010");
     label.push_back("0.0027");
     label.push_back("0.0100");
     label.push_back("0.0460");
     label.push_back("0.0500");
     label.push_back("0.1000");
     label.push_back("0.3170");
     label.push_back("0.5000");
     label.push_back("0.7000");    
     label.push_back("0.9000"); 
     
     mgr->Draw("ALP");
       
     Int_t i;
     for (i=1;i<=13;i++) {
       mgr->GetXaxis()->LabelsOption("d");
       int bin = mgr->GetXaxis()->FindBin(i);
       mgr->GetXaxis()->SetBinLabel(bin,label[i-1].c_str());
       
     }
     
     mgr->SetTitle("1-Dim");
     mgr->GetXaxis()->SetTitle("cut on p-value");
     mgr->GetYaxis()->SetTitle("fraction of survivors");
 
     mgr->Draw("ALP"); 
     
}