Polymorphic copy-constructor with type conversion

Question

I need to copy-construct an object simultaneously changing it\'s type to another class being a member of the same class-hierarchy. I\'ve read about polymorphic copy-constructors

Answer 1

c2 = (Child2*)c1->clone();

Here is a serious bug, and the c-style cast hides the bug.

If you use C++-style cast, then it will not hide the bug, and you will know it. In this case, the C++-style cast is : dynamic_cast. Use it to discover the bug yourself.

As it is clear from the code thatc1-clone() creates a clone of c1 whose type is Child1* and clone() returns a pointer of type Base* (after upcasting from Child1*), which you're trying to down-cast to Child2*. The cast should fail if you use proper cast : dynamic_cast.