【Weiss】【第03章】栈例程

写栈比队列更简单一些,毕竟只有一个数据出入口。

之前用C在程序里模拟栈代替递归的时候,直接搞个数组来实现都是非常轻松愉快的事情。

不多说,放代码。

测试代码

 1 #include <iostream>
 2 #include "stack.h"
 3 using namespace std;
 4 using namespace stack;
 5 template class Stack<int>;
 6 int main(void)
 7 {
 8     Stack<int> number;
 9 
10     //测试入栈
11     cout << "/*additem()*/" << endl;
12     number.push(2);
13     number.push(3);
14     number.push(5);
15     number.push(7);
16     number.push(11);
17     number.traverse();
18     cout << "
/*end*/

" << flush;
19 
20     //测试获取长度
21     cout << "/*length()*/" << endl;
22     cout << number.size() << endl;
23     cout << "/*end*/

" << flush;
24 
25     //测试获得头元素
26     cout << "/*getfirst()*/" << endl;
27     cout << number.getfirst() << endl;
28     cout << "/*end*/

" << flush;
29 
30     //测试出栈
31     cout << "/*remove()*/" << endl;
32     number.pop();
33     number.pop();
34     number.traverse();
35     cout << "
/*end*/

" << flush;
36 
37     //测试清空,并测试从空表中出栈
38     cout << "/*clear(),remove()*/" << endl;
39     number.clear();
40     number.pop();
41     cout << "/*end*/

" << flush;
42 
43     system("pause");
44 }
View Code

主体代码

  1 #ifndef STACK
  2 #define STACK
  3 #include <iostream>
  4 using namespace std;
  5 
  6 namespace stack
  7 {
  8 
  9 //节点模板
 10 template <typename T> struct Node
 11 {
 12     Node<T>() : next(nullptr){}
 13     Node<T>(const T &item, Node<T>* ptr = nullptr) : data(item), next(ptr){}
 14     T data;
 15     Node<T>* next;
 16 };
 17 //头节点及主体操作
 18 template <typename T> class Stack
 19 {
 20 //构造函数
 21 public:
 22     Stack<T>() : length(0), front(nullptr){}
 23 //接口
 24 public:
 25     //返回长度
 26     unsigned int size()const{ return length; }
 27     //返回头指针
 28     Node<T>* begin()const{ return front; }
 29     //判断是否为空
 30     bool empty()const{ return length == 0; }
 31     //获得头元素
 32     T getfirst()const{ return front->data; }
 33     //#查找元素所在地址
 34     Node<T>* find(const T &item)const;
 35     //#入栈
 36     bool push(const T &item);
 37     //#出栈
 38     bool pop();
 39     //#遍历并输栈元素
 40     void traverse()const;
 41     //#清空栈
 42     void clear();
 43 
 44 //辅助函数
 45 private:
 46     //#查找元素前驱
 47     Node<T>* find_prev(const T& item)const;
 48 //数据
 49 private:
 50     unsigned int length;
 51     Node<T>* front;
 52 };
 53 
 54 //如果元素为头元素或元素不存在则返回nullptr,否则返回前驱
 55 template <typename T> Node<T>* Stack<T>::find_prev(const T& item)const
 56 {
 57     if (length == 0)
 58         return nullptr;
 59     if (front->data == item)
 60         return nullptr;
 61     for (Node<T>* iter = front; iter->next != nullptr; iter = iter->next)
 62     {
 63         if (iter->next->data == item)
 64             return iter;
 65     }
 66     return nullptr;
 67 }
 68 //调用find_prev,如果元素存在则返回地址,不存在则返回nullptr
 69 template <typename T> Node<T>* Stack<T>::find(const T &item)const
 70 {
 71     Node<T>* iter = find_prev(item);
 72     if (length == 0)
 73         return nullptr;
 74     if (front->data == item)
 75         return front;
 76     return iter->next;
 77 }
 78 template <typename T> bool Stack<T>::push(const T &item)
 79 {
 80     Node<T>* pnew = new Node<T>(item);
 81     pnew->next = front;
 82     front = pnew;
 83     ++length;
 84     return true;
 85 }
 86 template <typename T> bool Stack<T>::pop()
 87 {
 88     if (length == 0)                    
 89     {
 90         cout << "No data!" << endl;
 91         return false;
 92     }
 93     Node<T>* save = front;
 94     front = front->next;
 95     delete save;
 96     --length;
 97     return true;
 98 }
 99 template <typename T> void Stack<T>::traverse()const
100 {
101     if (length != 0)
102     {
103         for (Node<T>* iter = front; iter != nullptr; iter = iter->next)
104             cout << iter->data << ends;
105     }
106 }
107 template <typename T> void Stack<T>::clear()
108 {
109     Node<T>* iter;
110     while (front != nullptr)
111     {
112         iter = front;
113         front = front->next;
114         delete iter;
115     }
116     front = nullptr;
117     length = 0;
118 }
119 }
120 #endif
原文地址:https://www.cnblogs.com/catnip/p/4328892.html