Queue的简单实现

代码如下:

  1 #ifndef QUEUE_H
  2 #define QUEUE_H
  3 #include "Exception.h"
  4 #include <deque>
  5 
  6 class EmptyQueueException : public Exception
  7 {
  8 public:
  9     EmptyQueueException()
 10         :Exception("read empty queue")
 11     { }
 12 };
 13 
 14 template <typename T, typename Container = std::deque<T> >
 15 class Queue
 16 {
 17 public:
 18 
 19     typedef T                                 value_type;
 20     typedef T&                                reference;
 21     typedef const T&                        const_reference;
 22     typedef Container                         container_type;
 23     typedef Container&                        container_reference;
 24     typedef const Container&                const_container_reference;
 25     typedef EmptyQueueException             exception_type;
 26     typedef typename Container::size_type     size_type;
 27 
 28 
 29     explicit Queue(const_container_reference cont = container_type())
 30         :_cont(cont)
 31     { }
 32 
 33     template <typename T2, typename Container2>
 34     Queue<T, Container>(const Queue<T2, Container2> &s);
 35 
 36     template <typename T2, typename Container2>
 37     Queue<T, Container> &operator=(const Queue<T2, Container2> &s);
 38 
 39     void push(const value_type &val) { _cont.push_back(val); }
 40 
 41     void pop()
 42     {
 43         if(_cont.empty())
 44             throw exception_type();
 45         _cont.pop_front();
 46     }
 47 
 48     reference front()
 49     {
 50         if(_cont.empty())
 51             throw exception_type();
 52         return _cont.front();
 53     }
 54 
 55     const_reference front() const
 56     {
 57         if(_cont.empty())
 58             throw exception_type();
 59         return _cont.front();
 60     }
 61 
 62     reference back()
 63     {
 64         if(_cont.empty())
 65             throw exception_type();
 66         return _cont.back();
 67     }
 68 
 69     const_reference back() const
 70     {
 71         if(_cont.empty())
 72             throw exception_type();
 73         return _cont.back();
 74     }
 75 
 76     bool empty() const { return _cont.empty(); }
 77     size_type size() const { return _cont.size(); }
 78 
 79     const_container_reference get_container() const
 80     { return _cont; }
 81 
 82     friend bool operator== (const Queue &a, const Queue &b)
 83     { return a._cont == b._cont; }
 84 
 85     friend bool operator!= (const Queue &a, const Queue &b)
 86     { return a._cont != b._cont; }
 87 
 88     friend bool operator>= (const Queue &a, const Queue &b)
 89     { return a._cont >= b._cont; }
 90 
 91     friend bool operator<= (const Queue &a, const Queue &b)
 92     { return a._cont <= b._cont; }
 93 
 94     friend bool operator> (const Queue &a, const Queue &b)
 95     { return a._cont > b._cont; }
 96 
 97     friend bool operator< (const Queue &a, const Queue &b)
 98     { return a._cont < b._cont; }
 99 private:
100     container_type _cont;
101 };
102 
103 template <typename T, typename Container>
104 template <typename T2, typename Container2>
105 Queue<T, Container>::Queue(const Queue<T2, Container2> &s)
106     :_cont(s.get_container().begin(), s.get_container().end())
107 { }
108 
109 template <typename T, typename Container>
110 template <typename T2, typename Container2>
111 Queue<T, Container> &Queue<T, Container>::operator= (const Queue<T2, Container2> &s)
112 {
113     if((void *)this != (void *)&s)
114     {
115         _cont.assign(s.get_container().begin(), s.get_container().end());
116     }
117     return *this;
118 }
119 #endif

测试代码如下:

 1 #include "stack.hpp"
 2 #include "queue.hpp"
 3 #include <iostream>
 4 #include <string>
 5 #include <vector>
 6 #include <list>
 7 #include <stdio.h>
 8 using namespace std;
 9 
10 int main(int argc, char const *argv[])
11 {
12 
13     try
14     {
15         Queue<string, vector<string> > st;
16         st.push("foo");
17         st.push("bar");
18 
19         Queue<string, list<string> > st2(st);
20         //st2 = st;
21 
22         while(!st2.empty())
23         {
24             cout << st2.front() << endl;
25             st2.pop();
26         }
27 
28         st2.pop(); //引发异常
29     }
30     catch (const Exception& ex)
31     {
32         fprintf(stderr, "reason: %s
", ex.what());
33         fprintf(stderr, "stack trace: %s
", ex.stackTrace());
34     }
35 
36     return 0;
37 }

测试结果如下:

foo
bar
reason: read empty queue
stack trace: ./a.out()
./a.out()
./a.out()
./a.out()
./a.out()
/lib/libc.so.6(__libc_start_main+0xe6)
./a.out()