C语言的画图（圆形动画）

#include <stdio.h>
#include <malloc.h>
#include<graphics.h>
#define LEN sizeof(struct student)
#include "math.h"
#define PI 3.1415926

void main()
{initgraph(680,680);

while(1)
{
BeginBatchDraw();
for(int y=100;y<480;++y)
{
setcolor(GREEN);
setfillstyle(YELLOW);
fillellipse(y-30,30,30+y,90); //里面的参数分别是fillellipse(左，上，右，下) 圆的边界

//getchar();
line(0,y,639,y);

FlushBatchDraw();
Sleep(20);
cleardevice();

}}
EndBatchDraw();
closegraph();
getchar();

}