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Thread: Hash Functions

  1. #1
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    Default Hash Functions

    Hi

    Do you guys know about Hash functions?

    Is there a library for this?

    Thanks a lot


  2. #2
    Administrator copeg's Avatar
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    Default Re: Hash Functions

    Hash functions is a very general term. What exactly do you need? A typical hash function uses multiplcation, addition, with a prime number in there somewhere to generate the hash. For example, a simple hash function for a class containing two values would be
    public class Test{
    	int var1;
    	int var2;
     
    	 @Override
    	public int hashCode() {
    		final int prime = 31;
    		int result = 1;
    		result = prime * result + var1;
    		result = prime * result + var2;
    		return result;
    	}
    }

    Eclipse can generate these for you.

  3. #3
    Super Moderator helloworld922's Avatar
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    Default Re: Hash Functions

    A hash function is simply a way to take the data inside an object and reduce it down to 1 number. This can be done any many ways. The important thing is that for the exact same object, this number must always be the same. The hash function should also attempt to be as "random" as possible between different objects, but it's near impossible to guarantee that a hash function will have no collisions.

    See: Hash function - Wikipedia, the free encyclopedia

  4. #4
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    Default Re: Hash Functions

    Hello i just stumbled upon this thread and i think that my library can help you. You can find its thread at GrandCentral and its project at http://code.google.com/p/grandcentral/

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