Integral of a histogram


I am trying to write a macro to obtain a histogram displaying the integrals of a large number of waveforms I have plotted using a function in the macro called “histWaveform”.

TH1F* histintegral = new TH1F("integral","integralspectrum; x value; y value", 100,-100,0);

  TCanvas* canvas = new TCanvas("spectrum","spectrum",1000,800);
  TLegend* leg = new TLegend(0.44,0.72,0.87,0.82);
   leg-> SetTextSize(0.028);
   leg-> SetFillColor(0);

 histintegral-> Draw();

 TH1F* waveIntegration (TH1F* histWaveform){

   double xmin = 0;
   double xmax = 4;

   TAxis *axis = histWaveform->GetXaxis();
   int bmin = axis->FindBin(xmin); 
  int bmax = axis->FindBin(xmax); 

  integral = (double) histWaveform->Integral(bmin,bmax);
   //printf("Number of DatPoints %d\n",bmax-bmin ); 
  printf(" %f\n", -integral);
 //integral -> cd()

   return integral;


Please do you have any suggestions?


Can you post a script which works ? thanks…