第5节 栈

 1 #include "linked_dclist.h" // for linked_dclist<T> 
 2  
 3 template <class T>
 4 class stack {
 5     typedef T value_type;
 6     typedef unsigned int s_size;
 7 public:
 8     // 构造函数
 9     stack() { }
10     // 拷贝构造函数
11     stack(const stack<T>& s) {
12         elem = s.elem;
13     }
14 
15     // 返回长度
16     s_size size() const {
17         return elem.size();
18     }
19 
20     // 清空栈
21     void clear() {
22         elem.clear();
23     }
24 
25     bool empty() const {
26         return elem.size() == 0;
27     }
28 
29     value_type get_top() const {
30         return elem[size()-1];
31     }
32     void push(const value_type& relem) {
33         elem.push_back(relem);
34     }
35 
36     // 删除栈顶元素，返回其值
37     value_type pop(){
38         try {
39             return elem.remove(size()-1);
40         }
41         catch (...) {
42             throw std::out_of_range("pop out_of_range");
43         }
44     }
45 
46     // 重载赋值运算符
47     stack<T>& operator = (const stack<T>& rhs) {
48         if (this == &rhs) 
49             return *this;
50         elem = rhs.elem;
51     }
52 
53     // 重载 "<<"
54     friend
55     ostream& operator << (ostream& out,stack<T>& rhs) {
56         cout << rhs.elem ;
57         return out;
58     }
59 
60 private:
61     linked_dclist<value_type> elem;    // 内部存储采用双向循环链表
62 };