2016整理版北邮面向对象C++试题（房鸣）(4)

int i;

public: };

void main() { }

改过之后： //main.cpp

#include

using namespace std; class A {

int i;

A& p1=*(A*)new B(); A& p2=*(A*)new C(10); !*p1;//结果：i=1

cout<<\结果：p2{i}=11 cout<<\结果：p2{i}=11 C(int x=2,int y):B(x),i(y){}

int operator+=(A& x){return i+=x.get();} int get(){return i;}

public: };

class B:public A { public:

B(int x=1):A(x){} //int get(){return i;} virtual int get(){return i;} virtual void operator!()=0;

virtual int operator+=(A& x){return 0;} virtual ~A(){} A(int x=0):i(x){}

};

//void operator!() {cout<<\void operator!() {cout<<\

class C:public B {

int i;

public: };

void main() { }

cout<<\结果：p2{i}=11 //insert delete &p1; delete &p2;

//cout<<\结果：p2{i}=11 cout<<\结果：p2{i}=11 //!*p1;//结果：i=1 !p1;//结果：i=1 A& p1=*(A*)new B(); A& p2=*(A*)new C(10); int get(){return i;}

//int operator+=(A& x){return i+=x.get();} int operator+=(A& x){return i+=x.A::get();} //C(int x=2,int y):B(x),i(y){} C(int y,int x=2):B(x),i(y){}