昨天給同事寫了一個把自定義型別作為map中key值的示例，結果過了半個小時，同事反饋：不滿足需求。

嗯哼？作為一個程式設計師，不滿足需求那可就是BUG呀~ 不行，得儘快給處理一下。

【1】異常示例（不滿足需求樣例）

原始碼如下：

 1 #include <map>
 2 #include <string>
 3 #include <iostream>
 4 using namespace std;
 5 
 6 struct SNCloneInfo
 7 {
 8     int cloneId;
 9     std::string type;
10 };
 
11 
12 struct SNCloneCompare
13 {
14     bool operator()(const SNCloneInfo& p1, const SNCloneInfo& p2) const
15     {
16         return (p1.cloneId < p2.cloneId) || (p1.cloneId == p2.cloneId && p1.type.size() < p2.type.size());
17     }
18 };
19 
20 struct SNCloneInfoRepo
21 {
22
 
     void create(SNCloneInfo src, SNCloneInfo dst)
23     {
24         m_mapRelations[src] = dst;
25     }
26     SNCloneInfo find(int id, std::string type)
27     {
28         return m_mapRelations[SNCloneInfo{ id, type }];
29     }
30 
31     std::map<SNCloneInfo, SNCloneInfo, SNCloneCompare> m_mapRelations;
32
 
 };
33 
34 int main()
35 {
36     SNCloneInfoRepo repo;
37     repo.create(SNCloneInfo{ 0, "abc" }, SNCloneInfo{ 0, "abc" });
38     repo.create(SNCloneInfo{ 0, "abcd" }, SNCloneInfo{ 1, "abc" });
39     repo.create(SNCloneInfo{ 0, "bcd" }, SNCloneInfo{ 1, "abc" });
40     repo.create(SNCloneInfo{ 1, "bcd" }, SNCloneInfo{ 0, "bcd" });
41     repo.create(SNCloneInfo{ 2, "cde" }, SNCloneInfo{ 0, "cde" });
42 
43     cout << "repo size : " << repo.m_mapRelations.size() << endl;
44     for (auto& item : repo.m_mapRelations)
45     {
46         cout << "K[ " << item.first.cloneId << "," << item.first.type << " ] -->"
47             << "V[ " << item.second.cloneId << "," << item.second.type << " ]" << endl;
48     }
49     auto temp = repo.find(0, "abc");
50     cout << "temp info cloneid :  " << temp.cloneId << " || type : " << temp.type << endl;
51 
52     return 0;
53 }

執行結果如下圖：

【2】正常示例（滿足需求樣例）

原始碼如下：

 1 #include <map>
 2 #include <string>
 3 #include <iostream>
 4 using namespace std;
 5 
 6 struct SNCloneInfo
 7 {
 8     int cloneId;
 9     std::string type;
10 };
11 
12 struct SNCloneCompare 
13 {
14     bool operator()(const SNCloneInfo& p1, const SNCloneInfo& p2) const
15     {
16         return (p1.cloneId < p2.cloneId) || (p1.cloneId == p2.cloneId && p1.type < p2.type);
17     }
18 };
19 
20 struct SNCloneInfoRepo
21 {
22     void create(SNCloneInfo src, SNCloneInfo dst)
23     {
24         m_mapRelations[src] = dst;
25     }
26     SNCloneInfo find(int id, std::string type)
27     {
28         return m_mapRelations[SNCloneInfo{ id, type }];
29     }
30 
31     std::map<SNCloneInfo, SNCloneInfo, SNCloneCompare> m_mapRelations;
32 };
33 
34 int main()
35 {
36     SNCloneInfoRepo repo;
37     repo.create(SNCloneInfo{ 0, "abc" }, SNCloneInfo{ 0, "abc" });
38     repo.create(SNCloneInfo{ 0, "abcd" }, SNCloneInfo{ 1, "abc" });
39     repo.create(SNCloneInfo{ 0, "bcd" }, SNCloneInfo{ 1, "abc" });
40     repo.create(SNCloneInfo{ 1, "bcd" }, SNCloneInfo{ 0, "bcd" });
41     repo.create(SNCloneInfo{ 2, "cde" }, SNCloneInfo{ 0, "cde" });
42 
43     cout << "repo size : " << repo.m_mapRelations.size() << endl;
44     for (auto& item : repo.m_mapRelations)
45     {
46         cout << "K[ " << item.first.cloneId << "," << item.first.type << " ] -->"
47             << "V[ " << item.second.cloneId << "," << item.second.type << " ]" << endl;
48     }
49     auto temp = repo.find(0, "abc");
50     cout << "temp info cloneid :  " << temp.cloneId << " || type : " << temp.type << endl;
51 
52     return 0;
53 }

執行結果如下圖：

【3】總結