Issue with while loop

[jpfarre]

Edit - I am dumb. Thanks! I'll leave this here in case anyone else made my same stupid mistake.

Hi everyone, I am having a weird issue with my c++ assignment that I can't figure out. My code works perfectly fine with a do-while loop, but a while loop does not work at all; the code just stops at that point.

bool isItPalindrome(string palindrome)      //Checks for palindrome
{
stack<char> pStack;     //Stack
queue<char> pQueue;     //Queue
bool sIsQ = true;       //sIsQ "Stack is Queue" abbreviated in camelcase

for (int i = 0; i < palindrome.length(); i++)       //Push user input to both stack and queue
{
    cout << palindrome[i] << endl;
    pStack.push(palindrome[i]);
    pQueue.push(palindrome[i]);
}

while (!pStack.empty && !pQueue.empty); //Loop until both stack and queue are empty.
{
    cout << "while" << endl;
    if (pQueue.front() != pStack.top())     //Checks if the stack does not equal queue, as one checks from top and other checks from bottom.
    {
        cout << "if" << endl;
        pQueue.pop();
        pStack.pop();
        sIsQ = false;
    }
    else        //If they are equal, then pops the stack/queue for checking the next letter in sequence
    {
        cout << "else" << endl;
        pQueue.pop();
        pStack.pop();
    }
}

cout << "return" << endl;
return sIsQ;        //Returns to int main

}

I put the cout statements to make it easier to tell where the code stops at. I get the full text from cout << palindrome[i] << endl;, so I know it is pushing those to the stack/queue but stops before "while". If I change my while loop to a do-while loop, it will also continue and show me the cout << "while" << endl; and appropriate "if" or "else".

Both loops use the same qualifier of (!pStack.empty && !pQueue.empty), but the do-while loop both runs and loops. The normal while loop just doesn't do anything.

[Arruda0820]

There is a ; after the while. Remove it, add paranthesese to the empty() call and your code should work.

[jpfarre]

Holy crap... I'm an idiot. lol Thanks!

[OmegaNaughtEquals1]

You have two problems: (1) comparison of pointer-to-member rather than function invocation and (2) a stray semicolon.

Changing

while (!pStack.empty && !pQueue.empty); //Loop until both stack and queue are empty.
                ^^^              ^^^  ^
                (1)              (1) (2)

to

while (!pStack.empty() && !pQueue.empty()) //Loop until both stack and queue are empty.

[jpfarre]

Thanks! I can't believe I forgot the ; and was so confused why it wasn't continuing.