Sword Point offer: Two stacks to implement a queue

Title: Implement a queue with two stacks. Implement its two functions Appendtail and Deletehead, respectively, to complete the function of inserting nodes at the end of the queue and deleting nodes at the head of the queue. The declaration of the queue is as follows:

  
 

   
  

  
template <typename T> class CQueue
   
  

  
{
   
  

  
public:
   
  

  
 CQueue(void);
   
  

  
 ~CQueue(void);
   
  

  
 
   
  

  
 // 在队列末尾添加一个结点
   
  

  
 void appendTail(const T& node);
   
  

  

   
  

  
 // 删除队列的头结点
   
  

  
 T deleteHead();
   
  

  

   
  

  
private:
   
  

  
 stack<T> stack1;
   
  

  
 stack<T> stack2;
   
  

  
};
  
 

  
 

   
  

  
template<typename T> void CQueue<T>::appendTail(const T& element)
   
  

  
{
   
  

  
 stack1.push(element);
   
  

  
} 
   
  

  

   
  

  
template<typename T> T CQueue<T>::deleteHead()
   
  

  
{
   
  

  
 if(stack2.size()<= 0)
   
  

  
 {
   
  

  
 while(stack1.size()>0)
   
  

  
 {
   
  

  
 T& data = stack1.top();
   
  

  
 stack1.pop();
   
  

  
 stack2.push(data);
   
  

  
 }
   
  

  
 }
   
  

  

   
  

  
 if(stack2.size() == 0)
   
  

  
 throw new exception("queue is empty");
   
  

  

   
  

  
 T head = stack2.top();
   
  

  
 stack2.pop();
   
  

  

   
  

  
 return head;
   
  

  
}
  
 

From for notes (Wiz)

Sword Point offer: Two stacks to implement a queue