Python栈实现异常：超出容量限制仍返回True未触发栈满错误

Let's break down and fix all the bugs in your Stack code that are causing it to never report being full, plus address other related problems:

Key Bugs Causing the "Never Full" Problem #

• Wrong capacity value: You want a stack that holds up to 6 elements, but you set self.StackSize = 5. Since top starts at 0 and increments after each push, this limits your stack to 5 elements max. Change this to self.StackSize = 6 to allow 6 elements.
• Broken isFull() method: The method uses StackSize instead of self.StackSize (it's an instance attribute, not a global/class variable). This would throw a NameError if called. Also, using self.top == self.StackSize is more efficient than checking len(self.stack).
• Method-attribute name conflict: You have a self.top integer attribute and a def top(self) method. This overwrites the attribute, making the method unusable and causing errors when trying to access the top element. Rename the method to peek() or get_top().

Other Fixes Needed #

• Broken getStack(): You can't concatenate a list directly to a string. Convert the stack to a string first with str().
• Typo in error message: The pop() method has a typo: "Stakc is empty" should be "Stack is empty".
• Recursion in test program: Calling main() after each operation will cause a recursion depth error with repeated use. Replace recursion with a loop.

Corrected Stack Class #

class Stack:
    def __init__(self):
        self.stack = list()
        self.StackSize = 6  # Updated to hold 6 elements
        self.top = 0

    def push(self, data):
        if self.top >= self.StackSize:
            return "Error! Error! Unable to perform function! Stack is full! Stack is full!"
        self.stack.append(data)
        self.top += 1
        return True

    def pop(self):
        if self.top <= 0:
            return "Error! Error! Unable to perform function! Stack is empty! Stack is empty!"  # Fixed typo
        item = self.stack.pop()
        self.top -= 1
        return item

    def isEmpty(self):
        return self.top == 0  # More efficient than checking list emptiness directly

    def isFull(self):
        return self.top == self.StackSize  # Fixed attribute access and logic

    def peek(self):  # Renamed from top() to avoid conflict
        if self.top > 0:
            return self.stack[-1]
        else:
            return "Stack is empty."

    def getStack(self):
        return "Stack: " + str(self.stack)  # Converted list to string

Corrected Test Program #

from Stack import Stack

def main():
    s = Stack()
    while True:
        print ("--- Menu of Options ---")
        print ("1: Add An Element To The Stack")
        print ("2: Remove The Top Element From The Stack")
        print ("3: Report Whether The Stack Is Empty")
        print ("4: Report Whether The Stack Is Full")
        print ("5: View The Top Element Of The Stack")
        print ("6: View The Entire Contents Of The Stack")
        print ("7: Exit Program")
        
        choice = input("\nPlease enter your choice: ")
        # Error handler for invalid choice
        while not choice in ("1", "2", "3", "4", "5", "6", "7"):
            print("\nInvalid entry. Please select from the menu provided.")
            choice = input ("\nPlease enter your choice: ")
        
        if choice == "1":
            x = input("Add an element to the stack: ")
            print(s.push(x))
        elif choice == "2":
            print(s.pop())
        elif choice == "3":
            print(s.isEmpty())
        elif choice == "4":
            print(s.isFull())
        elif choice == "5":
            print(s.peek())  # Updated to use renamed method
        elif choice == "6":
            print(s.getStack())
        else:
            print ("Ending Program")
            break  # Exit the loop instead of recursion

if __name__ == "__main__":
    main()

Now when you push 6 elements, the 7th push will return the stack full error, and the isFull() method will correctly return True once the stack is at capacity.

内容的提问来源于stack exchange，提问作者user14419453