範例

class Base {
public:
virtual void fnc();
};

class Derived: public Base {
public:
void fnc(){}
};

解決方案

當置換虛擬函數時，同時將衍生函數宣告為 virtual。

class Base {
public:
virtual void fnc();
};

class Derived: public Base {
public:
virtual void fnc(){}
};