用类实现二叉树

该二叉树：

　　

用类的方法进行定义：

#coding=utf-8

class btree(object):

    def __init__(self,root=None,left=None,right=None):
        self.root = root
        self.left = left
        self.right = right

    def get_left(self):
        return self.left

    def get_right(self):
        return self.right

    def get_root(self):
        return self.root

    def set_root(self,root):
        self.root = root

    def set_right(self,right):
        self.right = right

    def set_left(self,left):
        self.left = left


if __name__ == "__main__":


    tree = btree(root='a',left=btree(root='b',left='d',right='e'),right=btree(root='c',left='f',right='g'))

    print tree.get_left().get_left()