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Hello and welcome to this lecture.

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In this election.

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Are we talking to you.

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But Constance what are Constance.

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Constance are basically just like variables.

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So they have a lot of properties that variables have.

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One of the key differences between costers and variable is that with a constant their values are meant

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to remain fixed so they're meant to remain fixed.

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You can also still change them.

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That's what a constant variable should be.

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That is meant to have variables of values that are fit when you try to change the value of a constant.

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You get a warning from Ruby ghribi would tell you that this value you're trying to change is a constant.

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It should tell you that it has already initialized a value so it will give you a warning or don't elect

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to change it.

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You define constans just like you would variables.

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The only difference is that the first letter has to be an upper case.

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For example you can have a constant called sitting and the value is London so you can see the first

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letter is uppercase.

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Alright let's create a constant variable.

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I've got my interactive Ruby open.

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If you are on a Mac or lennix just type in ah be in to your terminal or shell and that should give you

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access to this.

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If you are on a Windows computer interactive Ruby can be accessed by your ruby Ford out you go to all

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programs and click on the road before that you got the icon for interactive Ruby.

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So I'm going to create a constant called C T.

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I just come here and type in the word city.

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Make sure the first letter is uppercase.

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I'm going to set the value to London.

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So if I do a put that put Furdo pause followed by the word City he should output London saw Let's try

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and change that value.

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So I'd type in city

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and set a new value.

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So say

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let's walk contrition by saying okay let's say I'd type in Orlando or London bombing regis's space.

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First let out capital or land.

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So watch what happens when I press enter.

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As you get a warning from Ruby Sears telling me that already initialise constant city have already initialized

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in value.

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So warning me that the previous definition of city was here so is telling me that he will change it.

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But this constant already has a value of core constants and not meant to have given his changed.

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So now if I time paim Puts city I should now get the value of Orlando he see.

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Change changes it.

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It gives you a warning before it does that.

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So that's how constants work solicit for this lecture on Constance.

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Thanks for watching.