Re: Polymorphism and inheritance
On 8 Sep, 11:22, Bart Friederichs <b...@tbwb.nl> 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)':
...
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?
TIA,
Bart
Bart,
Couple of things to get out of the way first:
1) There is no polymorphism at all. Polymorphism is when you have
virtual functions.
2) Child::foo() is illegal as it has two parameters called "i".
What you're attempting is overloading. When Child introduces a method
called foo, it hides all the other methods from its base classes with
the same name. You can still call it like this:
int main()
{
Child c;
int k = 0;
c.Parent::foo(k); // <--- We want to call Parent's foo()
}
Another alternative is to unhide foo with Parent like this:
class Parent {
public:
void foo(int i)
{
}
};
class Child : public Parent {
public:
void foo(int i, int j)
{
}
using Parent::foo; // <--- Unhide foo() from Parent
};
int main()
{
Child c;
int k = 0;
c.foo(k);
}
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