As stated in the System.HashCode documentation, adding together hashes returned by successive HashCode.Combine calls is NOT the solution. While the static HashCode.Combine method overloads only allow up to 8 values, these are just convenience methods – to combine more, instantiate the HashCode class itself and use it as follows: public override int GetHashCode() { HashCode … Read more
Easy! Since here is the implementation of the GetHashCode (sitting on the base class Delegate): public override int GetHashCode() { return base.GetType().GetHashCode(); } (sitting on the base class MulticastDelegate which will call above): public sealed override int GetHashCode() { if (this.IsUnmanagedFunctionPtr()) { return ValueType.GetHashCodeOfPtr(base._methodPtr); } object[] objArray = this._invocationList as object[]; if (objArray == null) … Read more
You can find the complete source code of the native methods here I hope this will work for you. These are native methods, because it has to interact with the machine. Here machine dependent code is written in the C language, which is not coming with the source package or in rt.jar of the lib … Read more
Why reinvent the wheel? Give Lodash a try. It has a number of must-have functions such as isEqual(). _.isEqual(object, other); It will brute force check each key value – just like the other examples on this page – using ECMAScript 5 and native optimizations if they’re available in the browser. Note: Previously this answer recommended Underscore.js, … Read more
The JavaDoc of Boolean.hashCode() method says: Returns the integer 1231 if this object represents true; returns the integer 1237 if this object represents false.
Whether you should do this depends on the semantics of your class. That is, what does it mean to say that two objects of your class are equivalent? The most important distinction is between objects with value semantics and objects with entity semantics. Entity objects are not equivalent even if they have equivalent attributes (colour, … Read more
There’s a free 1st edition of PinS that discuss this subject just as well. However, I think the best source is this article by Odersky discussing equality in Java. The discussion in PinS is, iirc, an abbreviated version of this article.
Using a power of two effectively masks out top bits of the hash code. Thus a poor-quality hash function might perform particularly badly in this scenario. Java’s HashMap mitigates this by mistrusting the object’s hashCode() implementation and applying a second level of hashing to its result: Applies a supplemental hash function to a given hashCode, … Read more
Finding two strings by repeatedly comparing random strings will take practically forever. Instead generate strings and store them in an a dictionary by hashcode. Then look up each. Match found pretty quickly. MATCH FOUND!! xqzrbn and krumld hash code 80425224 void Main() { var lookup = new Dictionary<int,string>(); while(true) { var s = RandomString(); var … Read more
hashCode is defined in java.lang.Object, so defining it in your own class doesn’t do much at all. (still it’s a defined method but it makes no difference) JIT has several ways to optimize call sites (in this case hashCode()): no overrides – static call (no virtual at all) – best case scenario with full optimizations … Read more