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#an exception to be raised by an empty stack
class EmptyStack(Exception):
pass
class Stack:
def __init__(self):
self._items = [] #non-public list for storing stack elements
def __len__(self):
return len(self._items)
def isEmpty(self):
return len(self) == 0
def push(self, e):
self._items.append(e) #add the element at the end of the list
def top(self):
if self.isEmpty():
raise EmptyStack("Stack Is Empty.")
return self._items[-1] #Return the last element in list
def pop(self):
if self.isEmpty():
raise EmptyStack("Stack Is Empty.")
return self._items.pop() #pop the last item from the list
# test the stack
S = Stack()
S.push("A")
S.push("B")
S.push("C")
print(S.pop())
print(S.pop())
print(S.pop())
print(S.pop())
xxxxxxxxxx
#an exception to be raised by an empty stack
class EmptyStack(Exception):
pass
class Stack:
def __init__(self):
self._items = [] #non-public list for storing stack elements
def __len__(self):
return len(self._items)
def isEmpty(self):
return len(self) == 0
def push(self, e):
self._items.append(e) #add the element at the end of the list
def top(self):
if self.isEmpty():
raise EmptyStack("Stack Is Empty.")
return self._items[-1] #Return the last element in list
def pop(self):
if self.isEmpty():
raise EmptyStack("Stack Is Empty.")
return self._items.pop() #pop the last item from the list
# test the stack
S = Stack()
S.push("A")
S.push("B")
S.push("C")
print(S.pop())
print(S.pop())
print(S.pop())
print(S.pop())