Histogram binning

Root Gurus,

The general way of making a histogram is thus:

TH1F *h1 = new TH1F(“h1”,"",100,0,100);

This gives a histogram with an X range from 0-100 with 100 bins.

Is there anyway to make it so that from X: 0-20, there are 100 bins, and then from X:21-100, there are 80 bins?

Thanks!

Make a variable bins’ size histogram:
root.cern.ch/root/html/TH1F.html#TH1F:TH1F