总结：
　　class CDerived2: virtual public CBase
　　{
　　public:
　　void fun(void) { }
　　virtual void vfun(void) { }
　　public:
　　int m_derived;
　　};
　　结果输出：
class CDerived2 size(20):
+---
0 | {vfptr}
4 | {vbptr}
8 | m_derived
+---
+--- (virtual base CBase)
12 | {vfptr}
16 | m_valuable
+---
CDerived2::$vftable@CDerived2@:
| &CDerived2_meta
|  0
0 | &CDerived2::vfun
CDerived2::$vbtable@:
0 | -4
1 | 8 (CDerived2d(CDerived2+4)CBase)
CDerived2::$vftable@CBase@:
| -12
0 | &CDerived2::fun
CDerived2::fun this adjustor: 12
CDerived2::vfun this adjustor: 0
vbi:    class  offset o.vbptr  o.vbte fVtorDisp
CBase      12       4       4 0
　　当中vftable@自身仅仅有一项：CDerived2::vfun()，vbtable@自身仅仅有一项：它virtual继承的父类CBase。而vftable@CBase原来的CBase::fun更新为CDerived2::fun。
　　CDerived3：virtual继承CBase，因此结构为vbtable@自身，member@自身。CBase结构
　　class CDerived3: virtual public CBase
　　{
　　public:
　　void fun(void) { }
　　public:
　　int m_derived3;
　　};
　　结果输出：
class CDerived3 size(16):
+---
0 | {vbptr}
4 | m_derived3
+---
+--- (virtual base CBase)
8 | {vfptr}
12 | m_valuable
+---
CDerived3::$vbtable@:
0 | 0
1 | 8 (CDerived3d(CDerived3+0)CBase)
CDerived3::$vftable@:
| -8
0 | &CDerived3::fun
CDerived3::fun this adjustor: 8
vbi:    class  offset o.vbptr  o.vbte fVtorDisp
CBase       8       0       4 0
CGDerived：继承CDerived2、CDerived3
class CGDerived: public CDerived2， public CDerived3
{
public:
void vfun() { }
virtual void vgfun() { }
public:
int m_gd;
};
　　输出：
class CGDerived size(32):
+---
| +--- (base class CDerived2)
0 | | {vfptr}
4 | | {vbptr}
8 | | m_derived
| +---
| +--- (base class CDerived3)
12 | | {vbptr}
16 | | m_derived3
| +---
20 | m_gd
+---
+--- (virtual base CBase)
24 | {vfptr}
28 | m_valuable
+---
CGDerived::$vftable@CDerived2@:
| &CGDerived_meta
|  0
0 | &CGDerived::vfun
1 | &CGDerived::vgfun
CGDerived::$vbtable@CDerived2@:
0 | -4
1 | 20 (CGDerivedd(CDerived2+4)CBase)
CGDerived::$vbtable@CDerived3@:
0 | 0
1 | 12 (CGDerivedd(CDerived3+0)CBase)
CGDerived::$vftable@CBase@:
| -24
0 | &thunk: this-=12; goto CDerived2::fun
CGDerived::vfun this adjustor: 0
CGDerived::vgfun this adjustor: 0
vbi:    class  offset o.vbptr  o.vbte fVtorDisp
CBase      24       4       4 0
　　因此首先是CDerived2的结构和CDerived3的结构，自己的新virtual方法vgfun则加入在左父类CDerived2的虚函数表中。然后是自己的成员。
　　后。CDerived2和CDerived3的父类CBase结构也带入当中。
　　它的fun默认指向CGDerived的左父类CDerived2::fun。
　　CGG：继承CGDerived
　　class CGG: public CGDerived
　　{
　　public:
　　int m_kc;
　　};
　　输出：
class CGG size(36):
+---
| +--- (base class CGDerived)
| | +--- (base class CDerived2)
0 | | | {vfptr}
4 | | | {vbptr}
8 | | | m_derived
| | +---
| | +--- (base class CDerived3)
12 | | | {vbptr}
16 | | | m_derived3
| | +---
20 | | m_gd
| +---
24 | m_kc
+---
+--- (virtual base CBase)
28 | {vfptr}
32 | m_valuable
+---
CGG::$vftable@CDerived2@:
| &CGG_meta
|  0
0 | &CGDerived::vfun
1 | &CGDerived::vgfun
CGG::$vbtable@CDerived2@:
0 | -4
1 | 24 (CGGd(CDerived2+4)CBase)
CGG::$vbtable@CDerived3@:
0 | 0
1 | 16 (CGGd(CDerived3+0)CBase)
CGG::$vftable@CBase@:
| -28
0 | &thunk: this-=16; goto CDerived2::fun
vbi:    class  offset o.vbptr  o.vbte fVtorDisp
CBase      28       4       4 0
　　添加一个变量，基本仅仅是把CGDerived的结构再套一层。后加上自己的成员变量。
　　vbtable所指向的父类结构依旧在后。
　　空类
　　class CBase2
　　{
　　};
　　输出：
　　class CBase2 size(1):
　　+---
　　+---
　　CD2：virtual继承则一定会创建vbtable，用vbptr指针指向，因此size为4
　　class CD2: virtual public CBase2
　　{
　　};
　　输出：
　　class CD2 size(4):
　　+---
　　0 | {vbptr}
　　+---
　　+--- (virtual base CBase2)
　　+---
　　CD2::$vbtable@:
　　0 | 0
　　1 | 4 (CD2d(CD2+0)CBase2)
　　vbi:    class  offset o.vbptr  o.vbte fVtorDisp
　　CBase2       4       0       4 0
　　CE：非virtual继承CD2和CDerived2。于是依照类的声明顺序，先带入CDerived2的结构，再带入CD2的结构（而不是按继承顺序）
　　class CE: public CD2， public CDerived2
　　{
　　};
　　输出：
class CE size(24):
+---
| +--- (base class CDerived2)
0 | | {vfptr}
4 | | {vbptr}
8 | | m_derived
| +---
| +--- (base class CD2)
12 | | {vbptr}
| +---
+---
+--- (virtual base CBase2)
+---
+--- (virtual base CBase)
16 | {vfptr}
20 | m_valuable
+---
CE::$vftable@CDerived2@:
| &CE_meta
|  0
0 | &CDerived2::vfun
CE::$vbtable@CD2@:
0 | 0
1 | 4 (CEd(CD2+0)CBase2)
2 | 4 (CEd(CE+12)CBase)
CE::$vbtable@CDerived2@:
0 | -4
1 | 12 (CEd(CDerived2+4)CBase)
CE::$vftable@CBase@:
| -16
0 | &thunk: this-=4; goto CDerived2::fun
vbi:    class  offset o.vbptr  o.vbte fVtorDisp
CBase2      16      12       4 0
CBase      16      12       8 0