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‫So now we'll create the hash function and this function will be used in the set function and the get

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‫function.

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‫I am going to bring up this graphic that we've been using to represent the hash function and then we'll

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‫start our code out like this.

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‫So we'll pass it a string, which is the key, and then this will return an integer, which is going

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‫to be the index where we store the key value pair.

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‫So we'll have a variable that we call hash that is an integer.

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‫We'll set that to be equal to zero to begin with, and then we'll create a for loop that will use to

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‫iterate over the key.

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‫So let's say the key is paint will iterate over these letters because it's basically an array of characters

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‫and then we'll have an integer that we call ASCII value and we'll set it equal to the key at the index

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‫of I as we're iterating over these letters.

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‫But notice that this key is a letter, but we're turning it into an integer.

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‫So to explain how we can do this, I'm going to flip over to a web browser and do a search for ASCII

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‫table.

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‫So I'll press enter.

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‫And what you can do with your search is just click on the first item returned and you'll get something

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‫that looks like this.

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‫So all of the letters that are in the key have an equivalent decimal value.

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‫So we said that the key was paint.

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‫The first letter is P.

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‫If we come down here, P has a value of 112, capital P has a different value.

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‫So now let's flip back.

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‫So this letter P, when we convert it into an integer, has the value of 112.

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‫So now we'll create our equation that we're going to use for our hash.

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‫We'll say hash equals and I'm going to set mine to be equal to hash plus ASCII value times 23.

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‫And the reason I multiply this by the number 23 is if you multiply it by a prime number, it makes the

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‫results more random.

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‫And now comes the really important part.

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‫We're going to say modulo.

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‫That's the percent sign there.

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‫And then we're going to use the size.

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‫So this is the size of data map, the address space.

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‫And we had set that size to be a constant of seven.

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‫So if you've never seen modulo before, what it does is it gives you the remainder when you divide.

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‫So if you divide by seven, the remainder can be anywhere from 0 to 6, and our address space goes zero

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‫through six.

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‫Now the only thing left to do is to return hash.

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‫And because we use this modulo operator up here with the size, this is always going to be an integer

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‫that will be zero through six.

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‫And that is our overview of the hash function.