void hist001_TH1_fillrandom() { // Create a one dimensional histogram and fill it with a gaussian distribution int nBins = 200; double rangeMin = 0.0; double rangeMax = 10.0; TH1D h1d("h1d", "Test random numbers", nBins, rangeMin, rangeMax); // "gaus" is a predefined ROOT function. Here we are filling the histogram with // 10000 values sampled from that distribution. h1d.FillRandom("gaus", 10000); // Open a ROOT file and save the histogram auto myfile = std::unique_ptr(TFile::Open("fillrandom.root", "RECREATE")); myfile->WriteObject(&h1d, h1d.GetName()); }