Re: Polymorphism and inheritance

From:
"Thomas J. Gritzan" <phygon_antispam@gmx.de>
Newsgroups:
comp.lang.c++
Date:
Mon, 08 Sep 2008 12:52:55 +0200
Message-ID:
<ga3067$lmi$1@newsreader2.netcologne.de>
Bart Friederichs wrote:

Hello,

I created the following inheritance:

class Parent {
public:
    void foo(int i);
};

class Child : public Parent {
public:
    void foo(int i, int i);
};

The following code fragment does not work (it doesn't compile, g++
complains about 'no matching function call for Child::foo(int)':


http://www.parashift.com/c++-faq-lite/strange-inheritance.html#faq-23.9

...
Child c;
int k = 0;
c.foo(k);
...

I assumed that by inheriting the base class, the 'Child' class would
have two 'foo' methods, with different parameters. Apparently not. Adding

void foo(int i) { Parent::foo(i); }

to the Child class, fixes it, but is that how it should be done? Why is
the Parent's foo() not polymorphised-inherited by Child?


The compiler only looked in the derived class for functions with name
"foo", found one and stopped. You have to tell it that there are more
functions of the same name, for example with a "using" declaration.

--
Thomas

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