#include "Queue.h"

// ====================測試代碼====================
void Test(char actual, char expected)
{
    if(actual == expected)
        printf("Test passed.\n");
    else
        printf("Test failed.\n");
}

int main(int argc, char* argv[])
{
    CQueue<char> queue;

    queue.appendTail(
 
‘a‘);
    queue.appendTail(‘b‘);
    queue.appendTail(‘c‘);

    char head = queue.deleteHead();
    Test(head, ‘a‘);

    head = queue.deleteHead();
    Test(head, ‘b‘);

    queue.appendTail(‘d‘);
    head = queue.deleteHead();
    Test(head, ‘c‘);

    queue.appendTail(‘e‘);
    head = queue.deleteHead();
    Test(head, 
 
‘d‘);

    head = queue.deleteHead();
    Test(head, ‘e‘);

    return 0;
}

 1 // 面試題9：用兩個棧實現隊列
 2 // 題目：用兩個棧實現一個隊列。隊列的聲明如下，請實現它的兩個函數appendTail
 3 // 和deleteHead，分別完成在隊列尾部插入結點和在隊列頭部刪除結點的功能。
 4 
 5 #pragma once
 6 #include <stack>
 7 #include <exception>
 8 #include<stdio.h>
 9
 
 #include<stdexcept>
10 
11 using namespace std;
12 
13 template <typename T> class CQueue
14 {
15 public:
16     CQueue(void);
17     ~CQueue(void);
18 
19     // 在隊列末尾添加一個結點
20     void appendTail(const T& node);
21 
22     // 刪除隊列的頭結點
23     T deleteHead();
24 
25 private:
26     stack<T> stack1;
27     stack<T> stack2;
28 };
29 
30 template <typename T> CQueue<T>::CQueue(void)
31 {
32 }
33 
34 template <typename T> CQueue<T>::~CQueue(void)
35 {
36 }
37 
38 template<typename T> void CQueue<T>::appendTail(const T& element)
39 {
40     stack1.push(element);
41 }
42 
43 template<typename T> T CQueue<T>::deleteHead()
44 {
45     if(stack2.size()<= 0)
46     {
47         while(stack1.size()>0)
48         {
49             T& data = stack1.top();
50             stack1.pop();
51             stack2.push(data);
52         }
53     }
54 
55     if(stack2.size() == 0){
56         std::logic_error ex("queue is empty");
57         throw std::exception(ex);
58     }
59 
60     T head = stack2.top();
61     stack2.pop();
62 
63     return head;
64 }

劍指offer——面試題9：用兩個棧實現隊列