#include "TCanvas.h"
#include "TH1.h"

Char_t amp_name[30]; 
Char_t hist_name[30];
Int_t Low, Up;
Char_t chrange[10],go[5];

int compare()
{

 cout << "compare histogrames with same name base from diffrent files" << endl;
  cout << "input the name_base: " << endl;
  cin >> name_base;
  cout << "input lower and upper limits of the histogram range:" << endl;
  cin >> Low;
  cin >> Up;

  /* open root files where historgrames are store */


  TFile f4("4.hist");
  TFile f51("51.hist");


  for (int i=1; i<=10; i++)
  {

    sprintf(hist_name, "%s_%d", name_base, i);
    cout << hist_name << endl;



    f4.cd(); 


    TH1D * hist1 = (TH1D *) f4.Get(hist_name);

    hist1->GetXaxis()->SetRange(Low,Up);
    hist1->SetLineColor(kRed); 
    hist1->Draw();
 

    /****  why no Canvas show up here ? ****/

    f51.cd();
    TH1D * hist2 = (TH1D *) f51.Get(hist_name);
    hist2->SetLineColor(kBlue);
    hist2->Draw("same");

    /**** no Canvas shows up here as well ****/


    cout << "Continue ?: (any character to contine)" << endl; 
    cin >> go;
  
  }

  return 0;

}