Question

[急求]使用虚函数编写程序求球体和圆柱体的体积及表面积.由于球体和圆柱体都可以看作由圆继承而来,所

Answer 1

#include

const double PI=3.14159265;

class circle

{ public:

circle(double r) { radius = r; }

virtual double area() { return 0.0; }

virtual double volume() { return 0.0; }

protected:

double radius;

};

class sphere:public circle

{ public:

sphere( double r ):circle( r ){ }

double area() { return 4.0 * PI * radius * radius; }

double volume()

{ return 4.0 * PI * radius * radius * radius / 3.0; }

};

class column:public circle

{ public:

column( double r,double h ):circle( r ) { height = h; }

double area()

{ return 2.0 * PI * radius * ( height + radius ); }

double volume()

{ return PI * radius * radius * height; }

private:

double height;

};

void main()

{ circle *p;

sphere sobj(2);

p = &sobj;

cout