java applet画一颗完全二叉树

package treedraw; import java.awt.*; class Interior extends Node //xfc { private Node left, right; public Interior(Node left, Node right) { this.left = left; this.right = right; } @Override public Point draw(java.awt.Graphics graphics, int depth) { Point leftLocation, rightLocation, location; leftLocation = left.draw(graphics, depth + 1); //先画左子节点，再画当前节点，再画右子节点，目的是使得当前节点有个合理的位置 graphics.fillOval(x, depth * SPACING, SIZE, SIZE); location = new Point(x + SIZE / 2, depth * SPACING + SIZE / 2); //节点的定位点是用几何中心来做的 x += SPACING; rightLocation = right.draw(graphics, depth + 1); graphics.drawLine(leftLocation.x, leftLocation.y, location.x, location.y); //链接左子节点和当前节点的线段 graphics.drawLine(rightLocation.x, rightLocation.y, location.x, location.y); //链接右子节点和当前节点的线段 return location; } }