我尝试使用堆栈和队列解决字符串回文问题，但面临逻辑问题

Question

Question: A palindrome is a string that reads the same forward and backward, for example, radar, toot, and madam. The challenge then is to write an algorithm that will read a sentence word-by-word from left to right and decide whether it is a palindrome. Palindrome strings as an example.

• “Madam, I'm Adam."
• “Eve."

The algorithm to solve this problem is relatively straightforward,

• Use a stack and a queue.
• Push and Enqueue tokens (words) into both data structures.
• Pop and Dequeue the tokens (words) and compare.
• Perform remove operation until one of the data structure is empty. If the case is that both are empty, the sentence is a palindrome.

Your task is to figure out whether the string entered by the user is a palindrome or not.

#include<iostream>
#include<string>
#include<stack>
#include<queue>
using namespace std;

#define MAX 1000

class Stack
{
    int top;
public:
    string myStack[MAX];

    Stack() { top = -1; }
    bool push(string item)
    {
        if (top >= (MAX - 1)) {
            cout << "Stack is full";
            return false;
        }
        else {
            myStack[++top] = item;
            cout << item << endl;
            return true;
        }
    }
    string pop()
    {
        if (top < 0) {
            cout << "Stack Underflow!!";
            return 0;
        }
        else {
            string item = myStack[top--];
            return item;
        }
    }
    bool isEmpty()
    {
     if (top == -1)
         return true;
     else
         return false;

    }
};

class Queue
{ public:
    string myqueue[MAX];
    int front, rear;
    Queue()
    {
         front = -1;
        rear = -1;
    }
    bool isFull() {
        if (front == 0 && rear == MAX - 1) {
            return true;
        }
        return false;
    }

    bool isEmpty() {
        if (front == -1) 
            return true;
        else 
            return false;
    }

    void enQueue(string item) {
        if (isFull()) {
            cout << endl << "Queue is full!!";
        }
        else {
            if (front == -1) front = 0;
            rear++;
            myqueue[rear] = item;
            cout << item << " "<<endl;
        }
    }
    string deQueue() {
        string value;
        if (isEmpty()) {
            cout << "Queue is empty!!" << endl;
            return false;
        }
        else {
            value = myqueue[front];
            if (front >= rear)
            {
                front = -1;
                rear = -1;
            }
            else {
                front++;
            }
            return(value);
        }
    }
};

int main()
{
    bool palindrome = true;
    Stack stack;
    stack.push("m");
    stack.push("a");
    stack.push("d");
    stack.push("a");
    stack.push("m");

    Queue queue;
    queue.enQueue("m");
    queue.enQueue("a");
    queue.enQueue("d");
    queue.enQueue("a");
    queue.enQueue("m");

    while (sizeof stack == 0 || sizeof queue == 0 )
    {
        stack.pop();
        queue.deQueue();
    };

    if (sizeof stack == sizeof queue )
    {
        cout << "The given word is palindrome." << endl;
    }
    else
    {
        cout << "The given word is not a palindrome." << endl;
    }

    system("pause");
    return 0;
}

Answer 1

Ah the magic of sizeof .

sizeof has a very specific meaning (which you can look up). It does not magically get you the size of anything you like, defined in whatever way you prefer.

This code

while (sizeof stack == 0 || sizeof queue == 0 )

should be

while (stack.isEmpty() || queue.isEmpty())

You wrote your isEmpty methods, you should use them.

But even that code is wrong (because of logical issues). I guessing (but not really sure) that you meant

while (!stack.isEmpty() && !queue.isEmpty())

In short sizeof has no place in this code. If you need to know the size of your stacks or queues you should write a method (called size maybe) that returns the size.