circle.cpp

教材例子

//程序CIRCLE.CPP(8.6.6)		功能：圆类CIRCLE的类实现
#include "figstack.h"
CIRCLE::CIRCLE(int x, int y, int r):FIGURE(x, y)
{
	radius=r;
}
void CIRCLE::show()
{
	if(!is_visible()){
		visible=TRUE;
		circle(x_pos, y_pos, radius);
	}
}
void CIRCLE::hide()
{
	int temp_color;
	if(is_visible()){
		temp_color=getcolor();
		setcolor(getbkcolor());
		visible=FALSE;
		circle(x_pos, y_pos, radius);
		setcolor(temp_color);
	}
}
void CIRCLE::expand(int delta)
{
	this->hide();
	if(delta>0) radius*=delta;
	else if(delta<0) radius/=-delta;
	this->show();
}