class Base
{
private:int x;
public:virtual void mf1() = 0;virtual void mf1(int){}virtual void mf2(){}void mf3(){}void mf3(double){}
};
class Derived :public Base
{
public:virtual void mf1(){}void mf3(){}void mf4(){}
};
/*
base class内所有名为mf1和mf3的函数都被derived class内的mf1和mf3函数遮掩掉
函数隐藏只与函数名称有关，与函数的参数类型、是否virtual无关，注意此处是静态绑定若通过指针或引用来调用虚函数，此时是动态绑定，不会发生函数隐藏
*/
int main()
{Derived d;int x = 1;d.mf1();//ok//d.mf1(x);//falsed.mf2();//okd.mf3();//ok//d.mf3(x);//false
system("pause");return 0;
}

class Base
{
private:int x;
public:virtual void mf1() = 0;virtual void mf1(int){}virtual void mf2(){}void mf3(){}void mf3(double){}
};class Derived :public Base
{
public:using Base::mf1;using Base::mf3;virtual void mf1(){}void mf3(){}void mf4(){}
};/*
如果你继承base class并且base class中有重载函数，而你又希望在派生类中重新定义其中一部分，那么你必须为那些
原本会被隐藏的每个名称引入一个using声明式，否则某些你希望继承的名称会被隐藏。using声明式会令继承而来的基类中某给定名称之所有同名函数在derived class中都可见
*/
int main()
{Derived d;int x = 1;d.mf1();//okd.mf1(x);//okd.mf2();//okd.mf3();//okd.mf3(x);//ok
system("pause");return 0;
}

class Shape
{
public:virtual void draw() const = 0{}virtual void error(const string& msg);int objectID() const;
};class Rectangle:public Shape
{
public:virtual void draw() const{}
};class Ellipse:public Shape
{
public:virtual void draw() const {}
};int main()
{//Shape *ps = new Shape;//error 抽象类不能生成实例Shape *ps1 = new Rectangle;ps1->draw();Shape *ps2 = new Ellipse;ps2->draw();ps1->Shape::draw();ps2->Shape::draw();system("pause");return 0;
}

class Shape
{
public:enum ShapeColor{Red,Green,Blue};virtual void draw(ShapeColor color = Red) const = 0;
};class Circle :public Shape
{
public:/*当用户以对象调用此函数，一定要指定参数值。因为静态绑定下这个函数并不从其基类继承缺省参数值。但若以指针或引用调用此函数，可以不指定参数值，因为动态绑定下这个函数会从其基类继承缺省参数值*/virtual void draw(ShapeColor color) const;
};