C++ Memory dump error resolved, Custom Queue class — Mallika Simone, Sarah Churng

For a while, we were struggling with a memory dump problem whenever we used the QueueArray structures in our code. About 2 weeks ago, we fixed them. In C++, when you pass an object as a function argument in C, it makes a copy of the object, instead of just calling it in reference. Which is fine for chars and ints and whatnot small objects. But since the built-in garbage collection will throw away that instance every call you make, it ends up building a new copy every single time you call the function*.

The fix: Use '&' in your calls to reference the object, rather than copy it. Here's our function getAverage, which returns the average of the contents of a QueueArray:

// Get Average of the contents of a queue of ints:

int getAverage(QueueArray <int>& qa){                    

  int sum = 0;                //the summation of values

  int cnt = qa.count();       //the count of distinct values

  

  while ( !qa.isEmpty() ) {

    sum = sum + qa.pop();

  }

  

  return ( sum / cnt );       //return the mean average 

}

Also, here's an override of QueueArrays, called Queue, which we are using because it has custom functions for our drunk-detection purposes:

class QueueNode {

  public:

    QueueNode(int val, QueueNode* next)

    {

     _val = val;

     _next = next;

    } 

    

    int _val;

    QueueNode* _next;

};

class Queue {

    public:

      Queue() {

        head = NULL; 

      }

      

      void Append(int val) {

        QueueNode* qn = new QueueNode(val, head);

        head = qn;

      };

      

      void Clear()       {

        QueueNode* cur = head;

        head = NULL;

        while (cur != NULL)

        {

         QueueNode* next = cur->_next;

         delete cur;

         cur = next;

        }

      }

      

      float Average() {

        int cnt = 0;

        int sum = 0;

        QueueNode* cur = head;

        while (cur != NULL) {

          cnt++;

          sum += cur->_val;

          cur = cur->_next;

        }

        

        if (cnt == 0)

          return 0.0;

        else

          return (float)sum/(float)cnt;

      }

    private:

      QueueNode* head;

};