how do hash tables work?

This is a discussion on how do hash tables work? within the C++ Programming forums, part of the General Programming Boards category; I'm reading up on hash tables and hashing functions and there's one thing that I don't get. A hashing function ...

  1. #1
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    how do hash tables work?

    I'm reading up on hash tables and hashing functions and there's one thing that I don't get. A hashing function takes a key and converts it into a memory address, right? What exactly is a key? Is it the same as an index in an array?

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    A key is the thing you want to use to refer to the piece of data.

    For example, if you are building a hash table of names to phone numbers, and you want to be able to look up the phone number given the name, the names would be the keys.

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    ok, so it's not a particular data type?

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    Nope, it can be any type, as long as it can be hashed.

    That's the purpose of the hashing function - to make the key an int (usually), so you can use it to index an array.

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