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?


Make a variable bins’ size histogram: