/*
 * DrawLine.c
 * the broken version
 */
 
extern void Plot(int x, int y);  /* plots a pixel on the screen */

/*
 * this function draws a line on the screen between (x0,y0) and (x1,y1),
 * but it has a few bugs.  Can you find them and fix them?
 */
void DrawLine(int x0, int y0, int x1, int y1) {
    int xmid, ymid;

    if(x0 == x1 && y0 == y1) return;

    xmid = (x0 + x1) / 2;
    ymid = (y0 + y1) / 2;

    Plot(xmid, ymid);

    DrawLine(x0, y0, xmid, ymid);
    DrawLine(xmid, ymid, x1, y1);
}