using namespace std;

class A{

public:

A(int i=0):r1(i){}

void print(){cout<<'E’<void print()const{cout<<'C'<void print(int x){cout<<'P'<private:

int r1;

};

int main(){

A a1;

const A a2(4);

(2);

();

return 0;

}

运行时的输出结果是

A)P8-E4

B)P8-C16-

C)P0-E4-

D)P0-C16-

(30)下列代码声明了3个类

class Person{};

class Student:public Person{};

class Undergraduate:Student{};

下列关于这些类之间关系的描述中，错误的是

A)类Person是类Undergraduate的基类

B)类Undergraduate从类Student公有继承

C)类Student是类Person的派生类

D)类Undergraduate是类Person的派生类

(31)有如下程序

#include

using namespace std;

Class Base{

public:

Base(int x=0):valB(x){cout<~Base(){cout<private:

int valB;

};

class Derived:public Base{

public:

Derived(int x=0,int y=0):Base(x),valD(y){cout<~Derived(){cout<private:

int valD;