C＃的IComparer< T>标准的使用问题 [英] C# IComparer<T> standard usage question

问题描述

我有这是否是在C＃中使用的IComparer标准的问题。说我有，其中有三个用户对象的情况：P1，P2和P3。说我叫传递P1和P2的比较方法，结果是0。这基本上意味着两个人应该被归类为相等。现在说我叫比较法传入P2和P3和的结果是0为好。同样，这意味着，两个人都相等。从逻辑上说，可以假设P1和P3也相等;然而，比较法可以实施然而有人决定来实现它。 ？因此，它是一个标准来实现它以这样一种方式，P1和P3也将在这种情况下返回0

这里是要问什么，我的代码：

  //假设这些都是正确初始化
的人P1 = NULL，P2 = NULL，P3 = NULL; 
的IComparer<&人GT;比较器= NULL; 
 
 //比较的人1到人2和结果是0 
 Debug.Assert的（comparer.Compare（P1，P2）== 0）; 
 
 //比较人2对人3和结果是0 
 Debug.Assert的（comparer.Compare（P2，P3）== 0）; 
 
 //这会是一个公平的假设，即人1和3人也将是0？ 
 Debug.Assert的（comparer.Compare（P1，P3）== 0）; 
  

解决方案

是的，这将是标准配置。它明确指出了IComparable的：

如果A.CompareTo（B）返回零和
B.CompareTo（C）返回零，那么
A.CompareTo（C）被要求返回
为零。

我找不到任何官方文件中附带的权利，并国ICompare同样的事情，但我认为它的安全承担同样如此。

I have a question with whether or not this is a standard for using IComparer in C#. Say I have a situation in which there are three Person objects: P1, P2, and P3. Say I call the Compare method passing in P1 and P2 and the result is 0. This essentially means the two people should be categorized as equal. Now say I call the Compare method passing in P2 and P3 and the result for that is 0 as well. Again, this means the two people are equal. Logically speaking, one can assume P1 and P3 are equal as well; however, the Compare method could be implemented however someone decides to implement it. So is it a standard to implement it in such a way that P1 and P3 would also return 0 in this case?

Here's code of what I'm asking:

// Assume these are initialized properly
Person p1 = null, p2 = null, p3 = null;
IComparer<Person> comparer = null;

// Compare person 1 to person 2 and result is 0
Debug.Assert(comparer.Compare(p1, p2) == 0);

// Compare person 2 to person 3 and result is 0
Debug.Assert(comparer.Compare(p2, p3) == 0);

// Would this be a fair assumption that person 1 and person 3 would also be 0?
Debug.Assert(comparer.Compare(p1, p3) == 0);

解决方案

Yes, that would be the standard. Its explicitly stated for IComparable:

If A.CompareTo(B) returns zero and B.CompareTo(C) returns zero, then A.CompareTo(C) is required to return zero.

I can't find anything in the official documentation that comes right out and states the same thing for ICompare but I think its safe to assume the same holds true.

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