C++ 注意事项

JonsenElizee

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#include <iostream>

using namespace std;

class SuperClass

{

public:

SuperClass():itsAge(1){ }

virtual ~SuperClass(){ }

virtual void doSomething() const{ cout << "SuperClassdoSomething!\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 (SuperClassx)

{

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;

}