问如何避免代码重复和使用常量成员和继承浪费内存？

EN

class Base
{
public:
    virtual int get_constant0() const = 0;
};

class Derived0 : public Base
{
public:
    virtual int get_constant0() const { return 5; }
};

class Derived1 : public Base
{
public:
    virtual int get_constant0() const { return 42; }
};