递归遍历二叉树

#二叉树结点
class BinaryTreeNode(object):
    def __init__(self):
        self.data='#'
        self.LeftChild=None
        self.RightChild=None

#二叉树类，创建二叉树和遍历二叉树
class BinaryTree(object):
    def CreateBinaryTree(self,Root):
        data=input('->')
        if data=='#':
            Root=None
        else:
            Root.data=data
            Root.LeftChild=BinaryTreeNode()
            self.CreateBinaryTree(Root.LeftChild)
            Root.RightChild=BinaryTreeNode()
            self.CreateBinaryTree(Root.RightChild)

    def PreOrder(self,Root):
        if Root is not None:
            self.VisitBinaryTreeNode(Root)
            self.PreOrder(Root.LeftChild)
            self.PreOrder(Root.RightChild)

    def InOrder(self,Root):
        if Root is not None:
            self.InOrder(Root.LeftChild)
            self.VisitBinaryTreeNode(Root)            
            self.InOrder(Root.RightChild)

    def PostOrder(self,Root):
        if Root is not None:
            self.PostOrder(Root.LeftChild)
            self.PostOrder(Root.RightChild)
            self.VisitBinaryTreeNode(Root)

    def VisitBinaryTreeNode(self,BinaryTreeNode):
        if BinaryTreeNode.data is not '#':
            print(BinaryTreeNode.data)
            

########################
#主程序
########################
bTN = BinaryTreeNode()
bT = BinaryTree()
print ('创建一棵二叉树\n')
print ('         4')
print ('        / \\')
print ('       5   6')
print ('      / \\  \\')
print ('     1   2  7 ')
print ('4 5 1 # # 2 # # 6 # 7 # #')
#创建一棵二叉树
print('请仿照上述序列，输入某一二叉树中各结点的值（#表示空结点），每输入一个值按回车换行：')
bT.CreateBinaryTree(bTN)
print ('对二叉树进行前序遍历:\n')
#前序遍历二叉树
bT.PreOrder(bTN)
print ('对二叉树进行中序遍历:\n')
#中序遍历二叉树
bT.InOrder(bTN)
print ('对二叉树进行后序遍历:\n')
#后序遍历二叉树
bT.PostOrder(bTN)

 

来源：CSDN

作者：tianrandai12

链接：https://blog.csdn.net/tianrandai12/article/details/104228953