Why histogram works with invalid Initialization Range?


I initialized histograms with TH1F(“xxx”, “XXX”, 10, 200, 100); and ROOT worked fine with this IMHO invalid object. It even filled histogram: goo.gl/0ME4p

Can someone explain me what happens?

if you read the documentation, you will see then when specifying a lower limit greater or equal to the lower limit, ROOT will automatically compute the best histogram boundaries at filling time.