The clear history just clear the whole thing back to 0 at once. While with the C button you have the possibility to just clear one number at the time if you put it in wrong. So you can access any history because there is no history in the calculator.
I went ahead and checked the options on the stock calculator under Android 4.1 and 4.2 and found no History option for previous results. There is a calculator in the Play store named RealCalc that has this function, plus the look and feel of a real LCD calculator. -Francis.
The clear history just clear the whole thing back to 0 at once. While with the C button you have the possibility to just clear one number at the time if you put it in wrong. So you can access any history because there is no history in the calculator.
