几何图形面积
classShape
{
public:
virtualdoublearea()=0;
};
classRectangle:publicShape
{
public:
Rectangle(doublew=1.0,doubleh=1.0)
{
width=w;
height=h;
}
doublearea()
{
returnwidth*height;
}
private:
doublewidth;
doubleheight;
};
classCircle:publicShape
{
public:
Circle(doubler=1.0)
{
radius=r;
}
doublearea()
{
return3.14159*radius*radius;
}
private:
doubleradius;
};