题目：学习putpixel画点，（在TC中实现）。
include "stdio.h"
include "graphics.h"
int main()
{
int i,j,driver=VGA,mode=VGAHI;
initgraph(&driver,&mode,"");
setbkcolor(YELLOW);
for(i=50;i<=230;i+=20)
for(j=50;j<=230;j++)
putpixel(i,j,1);
for(j=50;j<=230;j+=20)
for(i=50;i<=230;i++)
putpixel(i,j,1);
}
