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Popping, pushing, and expanding queues!

m4wk (32)
Hey guys, so I'm having some trouble with this program I am trying to write. Here is the main code: http://pastebin.com/y6yQX8K8

So, I have to write the functions to pop, push, and expand the q. Here is what I have for the pop:

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//function to pop
Order SandwichQueue::pop()
{
        if(isEmpty)
                return;
        --somevariable; //Not sure what this should be? 
}

and this is what I have so far for the push function:
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//push an element, make sure it is not full, if it is call expand funciton
void SandwichQueue::push(const Order& sw)
{

        if((rear+1) % qSize == front))          //Checks to see if the queue is full
                SandwichQueue::expandQ();       //Calls the expand function if full
        else
                sQ[++back] = sw;                //Assigns sw to sQ if not full.

}


I guess my questions are what should I be looking at for the decrementing in the pop function, and does the push function look correct? I would compile it but I'm missing the expand function, which I don't think I have covered in class yet; I can't just double size can I? Can anyone lend me some hints maybe?
m4wk (32)
So I've been messing with this more and I would like someone to please look at the functions I have written:
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//function to pop
Order SandwichQueue::pop()
{

        if(isEmpty())
                return NULL;
        front = (front + 1) % qSize;
        return Order[front];

}

//push an element, make sure it is not full, if it is call expand funciton
void SandwichQueue::push(const Order& sw)
{

        if(((back+1) % qSize == front))         //Checks to see if the queue is full
                SandwichQueue::expandQ();       //Calls the expand function if full
        back = (back + 1) % qSize;
        sQ[back] = sw;                          //Assigns sw to sQ if not full.
}

//Double the queue size, copy the values, and reset back and front
void SandwichQueue::expandQ()
{
        Order tempQ[initialSize * 2];

        for(int i = 0; i < size(); i++)
        {

                tempQ[i].sandwich = testCases[i].sandwich;
                tempQ[i].customerName = testCases[i].customerName;
                tempQ[i].orderNbr = testCases[i].orderNbr;
                tempQ[i].fries = testCases[i].fries;
        }

        delete [] testCases;
        *Order = tempQ;

        back = initialsize - 1;
        front = 0;

}

Questions I have are, in the pop function, how do I return the correct data? Order[front]? I'm not sure if I have it right, because then I'm confused in the push function because I have sQ[back]. Also, I'm not sure what I have done wrong in the expand function, or if it's close to being right at all.

Please someone help me :)
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