因为stack允许push或pop，所以只需简单地弹出用户的最新动作就可以重做动作。我有一个堆栈类：
class Node:
def __init__(self,item,the_next = None):
self.item = item
self.next = the_next
def __str__(self):
return str(self.item)
class LinkedStack:
def __init__(self):
self.top = None
self.count = 0
def __len__(self):
return self.count
def is_empty(self):
return self.count == 0
def isFull(self):
return False
def reset(self):
self.top = None
self.count = 0
def __str__(self):
current = self.top
ans = ""
while not (current is None):
ans += str(current)
ans += '\n'
current = current.next
return ans
def _get_node(self,index):
if 0<= index< len(self):
current = self.top
while index>0:
current = current.next
index -=1
return current
def pop(self):
if self.is_empty():
raise StopIteration("Stack is empty")
output = self.top.item
self.top = self.top.next
self.count -=1
return output
def push(self,item):
newNode = Node(item)
newNode.next = self.top
self.top = newNode
self.count +=1
if __name__ == "__main__":
L = LinkedStack()
在另一个文件中，我从上面导入堆栈并尝试实现撤消操作。
from Stack import LinkedStack
class Editor:
def __init__(self):
self.count = 0
self._list = LinkedList()
self._stack = LinkedStack()
def command(self,userCommand):
userCommand = userCommand.split(' ')
try:
if userCommand[0] == 'insert':
position = int(userCommand[1])
if len(userCommand) ==1:
raise Exception('no num is given')
textInput = input("Enter your text:")
self._stack.push(self.insertText(position,textInput)) #I'm thinking of adding the action into the stack by pushing it.
print(self._list)
pass
except Exception:
print('?')
if userCommand[0] == 'undo': #here if they choose to undo, by right i just pop the last action from the stack
self._stack.pop()
if __name__ == '__main__':
myCommand = Editor()
while True:
command = input('Enter an option:')
if command.lower() == 'quit':
break
else:
myCommand.command(command)
因为我只是撤消动作，我想把命令动作添加到堆栈中。如果你看一下上面的插入命令，我添加了一个注释，我正确地做了吗？因为我的想法已经不多了。
顺便说一句，insertText是一个有效的功能，我不打算将它粘贴在这里，因为它变得冗长。 LinkedList（）只是我从另一个文件导入的链表类。
＆＃39;撤消＆＃39;似乎没有恢复国家。例如，如果我的LinkedList（）包含：
1
2
3
4
None
如果我使用插入函数插入另一个数字，7在索引1
1
7
2
3
4
None
如果我撤消动作，我应该有：
1
2
3
4
None