Question

I don’t fully understand hashing algorithms. Anybody care to explain it to me in a very simply understandable way.

Thanks

EDIT: Using it with Usernames from a text file.

Answer 1

There are a lot of hashing algorithms, but the basic idea is to quickly and (nearly) uniquely come up with an identifier for a piece of data. This can then be used as an index into a table so that data can be quickly looked up. Most hash algorithms have collisions, where two pieces of data will hash to the same value, but this is extremely rare for the best algorithms.

For an example of why this might be useful, let’s say I hashed the entire phone book for my city. Now instead of doing a binary search when I want to look up someone’s number all I have to do is run their name through the hashing algorithm then go directly to that index in my table.