typeinfo

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2 total messages Started by John Max Skaller Mon, 29 Jan 1996 00:05

#3127

Author: John Max Skaller
Date: Mon, 29 Jan 1996 00:05

24 lines
1425 bytes

> class beatha{public:virtual ~beatha(){};}
> class duine:public beatha{};
> class gael: public duine {};
> 
> beatha *pd=new gael;
> if(typeid(pd)==typeid(duine)
> {       cout<<"duine";
> }
> ...
> does "duine" get printed here or not?

No. pd denotes an object of exact type "gael".
This is not the same type as "duine".
[Note "beatha" is polymorphic]

-- 
John Max Skaller               voice: 61-2-566-2189
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---
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Re: typeinfo

#3208

Author: steven2
Date: Fri, 02 Feb 1996 15:49

29 lines
1327 bytes

John Max Skaller <maxtal@suphys.physics.su.oz.au> wrote:

>> class beatha{public:virtual ~beatha(){};}
>> class duine:public beatha{};
>> class gael: public duine {};
>> 
>> beatha *pd=new gael;
>> if(typeid(pd)==typeid(duine)
>> {       cout<<"duine";
>> }
>> ...
>> does "duine" get printed here or not?

>No. pd denotes an object of exact type "gael".

I believe typeid (pd) is typeid (betha*). What I think you wanted is

if (typeid (*pd) == typeid (duine))

and so (typeid (*pd) == typeid (gael)) will evaluate to true.

Steve

[ comp.std.c++ is moderated.  Submission address: std-c++@ncar.ucar.edu.
  Contact address: std-c++-request@ncar.ucar.edu.  The moderation policy is
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