海绵图

#include <graphics.h>
#include <stdio.h>
void tria(xa,ya,xb,yb,xc,yc,n)
int xa,ya,xb,yb,xc,yc,n;
{
  int xp,yp,xq,yq,xr,yr;
  if (n>0)
  {
    xp=(xa+xb)/2;   yp=(ya+yb)/2;
    xq=(xb+xc)/2;   yq=(yb+yc)/2;
    xr=(xc+xa)/2;   yr=(yc+ya)/2;
    moveto(xp,yp);   lineto(xq,yq);
    lineto(xr,yr);   lineto(xp,yp);
    tria(xq,ya,xp,yp,xr,yr,n-1);
    tria(xb,yb,xq,yq,xp,yp,n-1);
    tria(xc,yc,xr,yr,xq,yq,n-1);
  }
}

main()
{
  int n=7,xa=10,ya=10,xb=10,yb=470,xc=630,yc=470;
  int gdrive=DETECT,gmode;
  initgraph(&gdrive,&gmode,"C:\\tc");
  cleardevice();
  setbkcolor(9);   setcolor(4);
  moveto(xa,ya);   lineto(xb,yb);
  lineto(xc,yc);   lineto(xa,ya);
  tria(xa,ya,xb,yb,xc,yc,n);
  getch();
  closegraph();
}