C++ 注意事项

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#include <iostream>

using namespace std ;

class SuperClass

{

public :

SuperClass ():itsAge (1) { }

virtual ~SuperClass () { }

virtual void doSomething () const { cout << "SuperClass doSomething!\n"; }

protected :

int itsAge ;

};

class SubClass : public SuperClass

{

public :

void doSomething ()const { cout << "SubClass doSomething!\n"; }

};

void PtrFunction (SuperClass * x )

{

x ->doSomething ();

}

void RefFunction (SuperClass & x )

{

x = (SuperClass )x ;

x .doSomething ();

}

void ValFunction (SuperClass x )

{

x .doSomething ();

}

int main ()

{

SuperClass * ptr =0;

ptr = new SubClass ;

PtrFunction (ptr );

RefFunction (*ptr );

ValFunction(*ptr); // 此处会调用到超类的doSomeThing方法

(*ptr ).doSomething ();

SuperClass x = (SuperClass )(*ptr );

x .doSomething ();

return 0;

}