stack
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class Stack:
def __init__(self):
self.items = []
def is_empty(self):
return len(self.items) == 0
def push(self, item):
self.items.append(item)
def pop(self):
if not self.is_empty():
return self.items.pop()
else:
return "Stack is empty"
def peek(self):
if not self.is_empty():
return self.items[-1]
else:
return "Stack is empty"
def size(self):
return len(self.items)
# Example usage
stack = Stack()
print("Is the stack empty?", stack.is_empty()) # True
stack.push(1)
stack.push(2)
stack.push(3)
print("Stack size:", stack.size()) # 3
print("Top item:", stack.peek()) # 3
print("Popped item:", stack.pop()) # 3
print("New top item:", stack.peek()) # 2
print("Stack size after pop:", stack.size()) # 2
Python
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