Function inorder

ParseTree.py:71–75

(tree)

# 递归实现中序遍历
def inorder(tree):
    if tree != None:
        inorder(tree.getLeftChild())
        print(tree.getRootVal())
        inorder(tree.getRightChild())

# 因为中序遍历会丢失括号信息, 因此尝试构造一个函数回复解析表达式
def printexp(tree):