#include iostreamusing namespace std;class Base1 public virtual void f cout Base1f endl; virtual void g cout Base1g endl; virtual void h cout Base1h endl; ;

Derived类的虚函数表示意图：

|-------------------| | Base1::f() | |-------------------| | Base1::g() | |-------------------| | Base1::h() | |-------------------| | Derive::f() | |-------------------| | 0x00000000 | |-------------------| | Base2::f() | |-------------------| | Base2::g() | |-------------------| | Base2::h() | |-------------------| | 0x00000000 | |-------------------| | Base3::f() | |-------------------| | Base3::g() | |-------------------| | Base3::h() | |-------------------| | 0x00000000 | |-------------------