2-1.c

小试验

#include<graphics.h>/*加入c图形库*/
#include<math.h>/*数学库*/
#include<conio.h>/*键盘控制*/
void MidpointCircle( int r,int value)
{
	int x,y;
	float d;
	x=0; y=r; d=1.25-r;
	putpixel(x,y,value);
	while(x<y)
	{
		if(getch()==17)exit();/*读入键盘按键*/
		if(d<0)
		{
			d+=2*x+3;
			x++;
		}
		else
		{
			d+=2*(x-y)+5;
			x++;
			y--;
		}
		putpixel(x,y,value);
	}
}

void main()
{
int i,driver,mode;
driver=DETECT;/*初始化显示模式参数*/
initgraph(&driver,&mode,"..\\bgi");/*初始化显示为默认驱动的640*480、16色模式*/
printf("Press any key to continue except 'Ctrl+Q' to quit.\n");
MidpointCircle(400,15);/*设置半径为400，颜色为15*/
closegraph();/*关闭图形模式*/
}