虚函数问题 [英] Virtual function question
问题描述
如果我有一个定义了虚函数的基类：
class CBase {
virtual void Foo（）;
};
无效CBase :: Foo（）
{
//基类功能
}
和一个覆盖基类Foo（）的派生类：
class CDerived： public CBase {
void Foo（）;
};
CDerived :: Foo（）
{
//派生功能
}
如果我有一个指向CDerived类型对象的指针，怎么能我打电话给基地
类版本的Foo（）而不是多态版本？
CDerived派生;
CDerived * p_derived =& derived ;
p_derived-> Foo（）; //想要以某种方式调用基类Foo（）！
我认为有一种简单的方法可以做到这一点，但我找不到它。
谢谢，
B
BCC发布：
如果我有一个定义了虚函数的基类：
类CBase {
virtual void Foo（）;
} ;
void CBase :: Foo（）
//
//基类功能
和派生类覆盖了基类Foo（）：
类CDerived：public CBase {
void Foo（）;
};
CDerived :: Foo（）
{
//派生的功能
如果我有一个指向CDerived类型对象的指针，我该如何调用Foo（）的基类版本比多态版本？
CDerived派生;
CDerived * p_derived =& derived;
p_derived-> Foo（）; //想以某种方式调用基类Foo（）！
p_derived-> CBase :: Foo（）;
-JKop
" BCC" <峰; br *** @ akanta.com>在留言中写道
news：kQ ******************* @ newssvr29.news.prodigy。 com ...
如果我有一个定义了虚函数的基类：
类CBase {
virtual void Foo（） ;
};
void CBase :: Foo（）
//
//基类功能
}
一个派生类，它覆盖基类Foo（）：
class CDerived：public CBase {
void Foo（）;
};
CDerived :: Foo（ ）
//
//派生的功能
如果我有一个指向CDerived类型对象的指针，我该如何调用基类
类版本的Foo（）而不是多态版本？
CDerived派生;
CDerived * p_derived =& derived;
p_derived-> Foo（）; //想以某种方式调用基类Foo（）！
我认为有一种简单的方法可以做到这一点，但我找不到它。
谢谢，
B
你确定要做那样的事吗？你有一个
派生类的对象，它定义了自己的行为，你想强迫它使用它的父亲的行为吗？我想你可能有设计问题。你试图告诉对象'自己的行为是不正确的。
DrX
< blockquote>
" BCC" <峰; br *** @ akanta.com>在留言中写道
news：kQ ******************* @ newssvr29.news.prodigy。 com ...
如果我有一个定义了虚函数的基类：
类CBase {
virtual void Foo（） ;
};
void CBase :: Foo（）
//
//基类功能
}
一个派生类，它覆盖基类Foo（）：
class CDerived：public CBase {
void Foo（）;
};
CDerived :: Foo（ ）
//
//派生的功能
如果我有一个指向CDerived类型对象的指针，我该如何调用基类
类版本的Foo（）而不是多态版本？
CDerived派生;
CDerived * p_derived =& derived;
p_derived-> Foo（）; //想以某种方式调用基类Foo（）！
我认为有一种简单的方法可以做到这一点，但我找不到它。
谢谢，
B
你能做什么（以及有意义的）如下：
class CBase {
public：
virtual void Foo（）{
... //基类行为
}
};
class CDerived：public CBase {
public：
void Foo（）{
:: Foo（）; //调用基类版本
... //扩展基类行为
}
};
Hi,
If I have a base class with a virtual function defined:
class CBase {
virtual void Foo();
};
void CBase::Foo()
{
// base class functionality
}
and a derived class which overrides the base class Foo():
class CDerived: public CBase {
void Foo();
};
CDerived::Foo()
{
// derived functionality
}
If I had a pointer to an object of type CDerived, how can I call the base
classes version of Foo() rather than the polymorphic version?
CDerived derived;
CDerived* p_derived = &derived;
p_derived->Foo(); // Want to somehow be able to call base class Foo()!
I think there is a simple way to do this, but I can''t find it.
Thanks,
B
BCC posted:
Hi,
If I have a base class with a virtual function defined:
class CBase {
virtual void Foo();
};
void CBase::Foo()
{
// base class functionality
}
and a derived class which overrides the base class Foo():
class CDerived: public CBase {
void Foo();
};
CDerived::Foo()
{
// derived functionality
}
If I had a pointer to an object of type CDerived, how can I call the base
classes version of Foo() rather than the polymorphic version?
CDerived derived;
CDerived* p_derived = &derived;
p_derived->Foo(); // Want to somehow be able to call base class Foo()!
p_derived->CBase::Foo();
-JKop
"BCC" <br***@akanta.com> wrote in message
news:kQ*******************@newssvr29.news.prodigy. com...Hi,
If I have a base class with a virtual function defined:
class CBase {
virtual void Foo();
};
void CBase::Foo()
{
// base class functionality
}
and a derived class which overrides the base class Foo():
class CDerived: public CBase {
void Foo();
};
CDerived::Foo()
{
// derived functionality
}
If I had a pointer to an object of type CDerived, how can I call the base
classes version of Foo() rather than the polymorphic version?
CDerived derived;
CDerived* p_derived = &derived;
p_derived->Foo(); // Want to somehow be able to call base class Foo()!
I think there is a simple way to do this, but I can''t find it.
Thanks,
B
Are you sure you want to do something like that? You have an object of a
derived class that defines its own behavior and you want to force it to use
its parent''s behavior? I think you may have a design problem. You are
trying to tell an object that''s own behavior is incorrect.
DrX
"BCC" <br***@akanta.com> wrote in message
news:kQ*******************@newssvr29.news.prodigy. com...Hi,
If I have a base class with a virtual function defined:
class CBase {
virtual void Foo();
};
void CBase::Foo()
{
// base class functionality
}
and a derived class which overrides the base class Foo():
class CDerived: public CBase {
void Foo();
};
CDerived::Foo()
{
// derived functionality
}
If I had a pointer to an object of type CDerived, how can I call the base
classes version of Foo() rather than the polymorphic version?
CDerived derived;
CDerived* p_derived = &derived;
p_derived->Foo(); // Want to somehow be able to call base class Foo()!
I think there is a simple way to do this, but I can''t find it.
Thanks,
B
What you can do (and what makes sense) is the following:
class CBase {
public:
virtual void Foo() {
... //base class behavior
}
};
class CDerived : public CBase {
public:
void Foo() {
::Foo(); // call base class version
... // extend base class behavior
}
};
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