状态模式（state）

 1 #include <iostream>
 2 #include <string>
 3 #include <map> //用户名，用户的下载
 4 using namespace std;
 5 
 6 class DownloadManager;
 7 class DownState {
 8 public:
 9     virtual void Down(string User, string DownItem, DownloadManager* p) = 0;
10 protected:
11     DownState(){}
12 };
13 
14 class NormalDownState :public DownState{
15 public:
16     void Down(string User, string DownItem, DownloadManager* p) {
17         cout << "欢迎您下载本资源" << endl;
18     }
19 };
20 class RepeateDownState :public DownState {
21 public:
22     void Down(string User, string DownItem, DownloadManager* p) {
23         cout << "请不要重复下载" << endl;
24     }
25 };
26 
27 class SpiteDownState :public DownState {
28 public:
29     void Down(string User, string DownItem, DownloadManager* p) {
30         cout << "你有恶意下载的嫌疑，即将取消下载资格" << endl;
31     }
32 };
33 
34 class BlackDownState :public DownState {
35 public:
36     void Down(string User, string DownItem, DownloadManager* p) {
37         cout << "您的下载过于频繁，被列入黑名单，禁止登录本系统" << endl;
38     }
39 };
40 
41 class DownloadManager {
42 public:
43     map<string, string> getMapDown() {
44         return m_mapDown;
45     }
46     void Down(string User, string DownItem) {
47         int oldDownCount = 0;
48         if (m_mapDownCount.count(User) > 0) {
49             oldDownCount = m_mapDownCount[User];
50         }
51         else {
52             m_mapDownCount[User] = 0;
53         }
54         oldDownCount++;
55         m_mapDownCount[User] = oldDownCount;
56         if (oldDownCount == 1) {
57             m_pState = new NormalDownState();
58         }
59         else if (oldDownCount > 1 && oldDownCount < 3) {
60             m_pState = new RepeateDownState();
61         }
62         else if (oldDownCount >= 3 && oldDownCount < 5) {
63             m_pState = new SpiteDownState();
64         }
65         else if (oldDownCount >= 5) {
66             m_pState = new BlackDownState();
67         }
68         m_pState->Down(User, DownItem, this);
69     }
70 private:
71     DownState* m_pState;//持有状态处理对象
72     map<string, string> m_mapDown;
73     map<string, int> m_mapDownCount;
74 };
75 
76 int main(void) {
77     DownloadManager* pVM = new DownloadManager;
78     for (int i = 0;i < 5;i++) {
79         pVM->Down("dst", "设计模式完全手册C++语言描述");
80     }
81     system("pause");
82     return 0;
83 }