Regarding Base & Derived Class

Question

I have two classes: Base and Derived. Now i create two objects : Derived d = new Derived() Base bd = new Derived() I want to know the difference between 'd' and 'bd' Thanks.

Benjamin Kemner · Answer

For runtime the instances d and db are exactly similar. The difference is that bd is declared to hold all derivated class types and the base class itself. This does matter if you have several derivated. i.g. Base |- Derived |- Derived2 |- Dervied3 Script: Base bd; if(userinput == 1) bd = new Derived(); else if(userinput == 2); bd = new Derived2(); else if(userinput == 3) bd = new Derived3(); else bd = new Base(); You see bd can hold all derived classes.