c++ get base class object from derived class pointer?

Question

Suppose I have Derived* derivedPtr;
I want Base baseObject from the derivedPtr;

Base baseObject = *derivedPtr; would create the baseObject with the appropriate Base class member variables?

Thank you

score 3 · Accepted Answer · edited May 23 '17 at 12:19

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Derived* obj = new Derived;
base objOne = (*obj) ;  // Object slicing. Coping only the  Base class sub-object
                        // that was constructed by eariler statement.

edited May 23 '17 at 12:19

Community

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answered Mar 22 '11 at 04:39

Mahesh

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score 2 · Answer 2 · answered Mar 22 '11 at 04:41

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You can use dynamic casting to accomplish this.

e.g.

Base* baseObject = dynamic_cast<Base*>(derivedPtr);

http://www.cplusplus.com/doc/tutorial/typecasting/

answered Mar 22 '11 at 04:41

Drooling_Sheep

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You don't need dynamic cast for this. You only need it for a cast from a Base to Derived. And since the OP wanted a new Base object, you don't need casting at all. :) – Xeo Mar 22 '11 at 04:43
Ah okay, Thanks. I was taught to err on the side of too much casting, so sometimes I forget when it's unnecessary. – Drooling_Sheep Mar 22 '11 at 04:53

Xeo · Answer 3 · 2011-03-22T04:45:06.363

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Yes. That's actually called 'slicing', since you just slice off everything from the derived class.

edited Mar 22 '11 at 04:45

answered Mar 22 '11 at 04:37

Xeo

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c++ get base class object from derived class pointer?

3 Answers3