Arnb,
1. FIRST CODE - overloading
2. SECOND CODE - This is not a valid overriding or overloading. That is the reason for compilation error.
3. THIRD CODE - same as above
4. FOURTH CODE - This is Overriding.
5. FIFTH CODE - This is Overriding.
6. SIXTH CODE - This is also Overriding. But, compilation error because base class object can't be assigned to a subclass reference(class2 c2 = new class2Base()
.
Hope this helps.