二叉树遍历

package com.wujie.tree;

public class Tree {
	
	public static void main(String[] args) {
		
		TreeNode root = new TreeNode("Root");
		TreeNode a = new TreeNode("A");
		TreeNode b = new TreeNode("B");
		TreeNode c = new TreeNode("C");
		TreeNode d = new TreeNode("D");
		TreeNode e = new TreeNode("E");
		TreeNode f = new TreeNode("F");
		TreeNode g = new TreeNode("G");
		TreeNode h = new TreeNode("H");
		
		root.left = a;
		root.right = b;
		a.left = e;
		a.right = f;
		b.left = g;
		g.right = h;
		
		root.firstList(root);
		System.out.println();
		root.midList(root);
		System.out.println();
		root.endList(root);
		
		
		
	}
	
	

}

class TreeNode {
	
	public String element;
	
	public TreeNode left;
	
	public TreeNode right;
	
	public TreeNode(String element) {
		this.element = element;
	}
	
	/**
	 * 	先序遍历
	 */
	public void firstList(TreeNode root) {
		
		System.out.print(root.element + "->");
		
		if (root.left != null) {
			this.firstList(root.left);
		}		
		if (root.right != null) {
			this.firstList(root.right);
		}
			
	}
	
	/**
	 * 	中序遍历
	 */
	public void midList(TreeNode root) {
		
		if (root.left != null) {
			this.midList(root.left);
		}
		
		System.out.print(root.element + "->");
		
		if (root.right != null) {
			this.midList(root.right);
		}
			
	}
	
	/**
	 * 	后序遍历
	 */
	public void endList(TreeNode root) {
		
		if (root.left != null) {
			this.endList(root.left);
		}
		
		
		if (root.right != null) {
			this.endList(root.right);
		}
			
		System.out.print(root.element + "->");
	}
	
	
}