《面向对象程序设计c++》期末试卷及标准答案(a) ()

B::~B() called.

A::~A() called. 4、Call B's function f() Call B's function g() Call C's function g() 四、编程题（共27分） 1、（10分）

Complex::Complex(){real=0;imag=0;} Complex::Complex(double r){real=r;}

Complex::Complex(double r,double i){real=r;imag=i;} Complex operator+(Complex &c1,Complex &c2) { Complex c;

c.real=c1.real+c2.real; c.imag=c1.imag+c2.imag; return c; }

ostream& operator << (ostream& output,Complex& c) { output<<\ return output; }

istream& operator >> (istream& input,Complex& c)

{ cout<<\ input>>c.real>>c.imag; return input; }

2、（17分）

class Circle:public Shape {public:

Circle(double r){radius=r;} void set() { cout<<\ cin>>radius;

}

void show()

{

cout<<\

double area() {return 3.14159*radius*radius;} private: double radius;

};

class Square:public Shape {public:

Square(double a){this->a=a;} void set() { cout<<\ cin>>a;

}

void show()

{

cout<<\

}

double area(){return a*a;} private: double a;

}; int main()

}

{ }

Circle C(5.5); C.show(); Square S(9.9); S.show();

Shape *s[]={&C,&S};

cout<<\return 0;