Is Légal’s reported “psychological trick” considered fair play or unacceptable conduct under FIDE rules?
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The following example creates two identical 3-tuple objects whose components consist of three Double values. The value of the second component is Double.NaN. The example then calls the Tuple.Equals method, and it calls the IStructuralEquatable.Equals method three times. The first time, it passes the default equality comparer that is returned by the EqualityComparer.
Default property. The second time, it passes the default equality comparer that is returned by the StructuralComparisons.StructuralEqualityComparer property. The third time, it passes the custom NanComparer object. As the output from the example shows, the first three method calls return true, whereas the fourth call returns false.
This code technically works, but is sort of a hot mess and is derece really maintainable. Anyone using the library would have to write this code as well. The next logical step would be to just use .Equals on the entire metrics.
Your concern is that Object.GetHashCode() does not provide values that are stable and the concern is very valid as sevimli be seen in the first box headed by Caution in the documentation:
What does IEquatable buy you, exactly? The only reason I can see it being useful is when creating a generic type and forcing users to implement and write a good equals method.
I've noticed these two interfaces, and several associated classes, have been added in .Kupkuru 4. They seem a bit superfluous to me; I've read several blogs about them, but I still güç't figure out what sıkıntı they solve that was tricky before .Kemiksiz 4.
Ray BooysenRay Booysen 29.6k1414 gold badges8686 silver badges111111 bronze badges 6 so when you are dealing with objects, is == assumed to only mean the exact same memory address (same instance)
I had the same question. When I ran LBushkin's example I was surprised to see that I got a different answer! Even though that answer saf 8 upvotes, it is wrong. After a lot of 'reflector'ing, here is my take on things.
To achieve this, employee objects with matching SSN properties would be treated birli logically equal, even if they were derece structurally equal. Share Improve this answer Follow
That is, you yaşama create your own definition of structural equality and specify that this definition be used with a collection type that accepts the IStructuralEquatable interface. The interface has two members: Equals, which tests for equality by using a specified IEqualityComparer implementation, and GetHashCode, which returns identical hash codes for objects that are equal.
Here the comparison is different for value type arrays and custom arrays. In .Kupkuru 4.0 int, string will internally implement IEquatable C# IStructuralEquatable nedir for custom types we have to externally implement the IEquatable.
The Equals method supports custom structural comparison of array and tuple objects. This method in turn calls the comparer object's IEqualityComparer.Equals method to compare individual array elements or tuple components, starting with the first element or component.