错误C2660：'Aba :: f'：函数未使用0个参数

Question

I want to know why there is an error in the following function:

#include<iostream>

using namespace std;
class Saba

{

public:

    Saba(){ cout << "Saba Ctor" << endl; }

    Saba(const Saba& a){ cout << "Saba Copy Ctor" << endl; }

    ~Saba(){ cout << "Saba Dtor" << endl; }

    virtual void f(){ cout << "Saba f()" << endl; }

    virtual void g(){ cout << "Saba g()" << endl; }

    void h(){ cout << "Saba h()" << endl; }

};

class Aba : public Saba

{

public:

    Aba(){ cout << "Aba Ctor" << endl; }

    Aba(const Aba& a){ cout << "Aba Copy Ctor" << endl; }

    ~Aba(){ cout << "Aba Dtor" << endl; }

    virtual void g(){ cout << "Aba g()" << endl; }

    virtual void f(int){ cout << "Aba f(int)" << endl; }

    virtual void h(){ cout << "Aba h()" << endl; }

};

class Son : public Aba

{

public:

    Son(){ cout << "Son Ctor" << endl; }

    Son(const Son& a){ cout << "Son Copy Ctor" << endl; }

    ~Son(){ cout << "Son Dtor" << endl; }

    void f(){ cout << "Son f()" << endl; }

    void h(){ cout << "Son h()" << endl; }

};

int main()

{

    Saba* sabaPtr = new Son();

    Aba* abaPtr =dynamic_cast<Aba*>(sabaPtr);

    abaPtr->f();

    abaPtr->g();

    abaPtr->h();

    delete sabaPtr;

    return 0;

}

I get an error " error C2660: 'Aba::f' : function does not take 0 arguments". But "aba" inherited from "saba" so he can use f() of "saba"

Answer 1

Aba::f , which takes 1 parameter, hides the Saba::f . That is why when you call Aba::f with no argument the compiler complains. Just for your information clang gave me those warnings :

main.cpp:38:18: warning: 'Aba::f' hides overloaded virtual function [-Woverloaded-virtual]

virtual void f(int){ cout << "Aba f(int)" << endl; }
             ^

main.cpp:38:18: note: hidden overloaded virtual function 'Aba::f' declared here: different number of parameters (1 vs 0)

virtual void f(int){ cout << "Aba f(int)" << endl; }

Answer 2

I don't know what did you expect while writing your code but it works correctly.

During initialization you've casted pointer from Saba to Aba in:

Aba* abaPtr = dynamic_cast<Aba*>(sabaPtr);

So, abaPtr is proper Aba object (of course if dynamic cast was successfull). Next, in the line

abaPtr->f();

you are calling Aba::f(int) which expects 1 argument to specified while you don't specify it.