(31)有如下程序：
#include
using namespace std;
class Base
{
private:
void funl() const{cout<<"funl";}
protected:
void fun2() const{cout<<"fun2";}
public:
void fun3() const{cout<<"fun3";}
};
class Derived:protected Base
{
public:
void fun4() const{cout<<"fun4";}
};
int main()
{
Derived obj;
obj.funl(); //①
obj.fun2(); //②
obj.fun3(); //③
obj.fun4(); //④
return 0;
}
其中有语法错误的语句是
A．①②③④
B．①②③
C．②③④
D．①④
(32)有如下程序：
#include
using namespace std;
class Base
{
public:
void funl(){cout<<"Base\n";}
virtual void fun2(){cout<<"Base\n";}
};
class Derived:public Base
{
public:
void funl(){cout<<"Derived\n";}
void fun2(){cout<<"Derived\n";}
};
void f(Base &
B．{b.funl();b.fun2();}&, lt;, /P>
int main()
{
Derived obj;
f(obj);
return 0;
}
执行这个程序的输出结果是
A．Base
B．Base
C．Derived
D．Derived
Base Derived Base Derived
(33)有如下程序：
#include
using namespace std;
class Complex
{
double re, im;
public:
Complex(double r, double i):re(r), im(i){}
double real() const{return re;}
double image() const{return im;}
Complex& operator +=(Complex a)
{
re += a.re;
im += a.im;
return *this;
}
};
ostream &operator<<(ostream& s,const Complex& z)
{
return s<<'('<
}
int main()
{
Complex x(1, -2), y(2, 3);
cout<<(x += y)<
return 0;
}
执行这个程序的输出结果是
A．(1, -2)
B．(2, 3)
C．(3, 5)
D．(3, 1)
(34)有如下程序：
#include
#include
using namespace std;
int main()
{
cout.fill('*');
cout<
return 0;
}
执行这个程序的输出结果是
A．123*OK
B．123*OK**
C．*123OK
D．*123**OK
(35)有如下类声明：
class SAMPLE
{
int n;
public:
SAMPLE (int i = 0): n(i){}
void setvalue(int n0);
};
下列关于setvalue成员函数的实现中，正确的是
A．SAMPLE::setvalue(int n0){n = n0;}
B．void SAMPLE::setvalue(int n0){n = n0;}
C．void setvalue(int n0){n = n0;}
D．setvalue(int n0){n = n0;}
责任编辑：cyth
