Selecting Median from Data Streams

class MedianFinder {
public:
      priority_queue<int>max_heap;
      priority_queue<int,vector<int>,greater<>>min_heap;
    MedianFinder() {
    
    }
    
    void addNum(int num) {
        if(max_heap.size()==0&&min_heap.size()==0)
            max_heap.push(num);
        else if(max_heap.size()>0)
        {
            if(max_heap.top()<=num)
                min_heap.push(num);
            else
                max_heap.push(num);
            if((max_heap.size()-min_heap.size())<=1)
                return;
            if(max_heap.size()>min_heap.size())
            {
                int top=max_heap.top();
                max_heap.pop();
                min_heap.push(top);
                
            }
            else
            {
                 int top=min_heap.top();
                min_heap.pop();
                max_heap.push(top);
            }
        }
        return;
    }
    
    double findMedian() {
        double d;
        if(max_heap.size()==min_heap.size())
        {
            double d1= max_heap.top();
            double d2 = min_heap.top();
            d = (d1+d2)/2.0;
            return d;
        }
        else if(max_heap.size()>min_heap.size())
            {
                double top=max_heap.top();
              
                return top;
            }
        else
        {
            double top=min_heap.top();
              
                return top;
        }
    }
};

/**
 * Your MedianFinder object will be instantiated and called as such:
 * MedianFinder* obj = new MedianFinder();
 * obj->addNum(num);
 * double param_2 = obj->findMedian();
 */