这道题面试的时候经常遇到，特此收录。全部代码来自《剑指offer》。

template 
     
       class CQueue{public:    CQueue(void);    ~CQueue(void);    void appendTail(const T &node);    T deleteHead();private:    stack
      
        stack1;    stack
       
         stack2;};template 
        
         void CQueue
         
          ::appendTail(const T &node){    stack1.push(node);}template 
          
           T CQueue
           
            ::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;}
           
          
         
        
       
      
     

LeetCode上一道题 

 solution：

class Queue {private:    stack
     
       stk1, stk2;public:    // Push element x to the back of queue.    void push(int x) {        stk1.push(x);    }    // Removes the element from in front of queue.    void pop(void) {        peek();        stk2.pop();    }    // Get the front element.    int peek(void) {        if (stk2.empty())        {            while (stk1.size() > 0)            {                stk2.push(stk1.top());                stk1.pop();            }        }        return stk2.top();    }    // Return whether the queue is empty.    bool empty(void) {        return stk1.empty() && stk2.empty();    }};
     

PS:

　　两个队列实现一个栈

LeetCode上一道题： 

solution：    //使用一个队列实现栈

class Stack {private:    queue
     
       que;public:    // Push element x onto stack.    void push(int x) {        que.push(x);        for (int i = 0; i < que.size()-1; ++i)        {            que.push(que.front());            que.pop();        }    }    // Removes the element on top of the stack.    void pop() {        que.pop();    }    // Get the top element.    int top() {        return que.front();    }    // Return whether the stack is empty.    bool empty() {        return que.empty();    }};