class StackOverflowError(BaseException): pass class Stack: """A stack is an abstract data type that serves as a collection of elements with two principal operations: push() and pop(). push() adds an element to the top of the stack, and pop() removes an element from the top of a stack. The order in which elements come off of a stack are Last In, First Out (LIFO). https://en.wikipedia.org/wiki/Stack_(abstract_data_type) """ def __init__(self, limit: int = 10): self.stack = [] self.limit = limit def __bool__(self) -> bool: return bool(self.stack) def __str__(self) -> str: return str(self.stack) def push(self, data): """ Push an element to the top of the stack.""" if len(self.stack) >= self.limit: raise StackOverflowError self.stack.append(data) def pop(self): """ Pop an element off of the top of the stack.""" return self.stack.pop() def peek(self): """ Peek at the top-most element of the stack.""" return self.stack[-1] def is_empty(self) -> bool: """ Check if a stack is empty.""" return not bool(self.stack) def is_full(self) -> bool: return self.size() == self.limit def size(self) -> int: """ Return the size of the stack.""" return len(self.stack) def __contains__(self, item) -> bool: """Check if item is in stack""" return item in self.stack def test_stack() -> None: """ >>> test_stack() """ stack = Stack(10) assert bool(stack) is False assert stack.is_empty() is True assert stack.is_full() is False assert str(stack) == "[]" try: _ = stack.pop() assert False # This should not happen except IndexError: assert True # This should happen try: _ = stack.peek() assert False # This should not happen except IndexError: assert True # This should happen for i in range(10): assert stack.size() == i stack.push(i) assert bool(stack) is True assert stack.is_empty() is False assert stack.is_full() is True assert str(stack) == str(list(range(10))) assert stack.pop() == 9 assert stack.peek() == 8 stack.push(100) assert str(stack) == str([0, 1, 2, 3, 4, 5, 6, 7, 8, 100]) try: stack.push(200) assert False # This should not happen except StackOverflowError: assert True # This should happen assert stack.is_empty() is False assert stack.size() == 10 assert 5 in stack assert 55 not in stack if __name__ == "__main__": test_stack()