WEBVTT

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So we saw before we could pass in values to functions so you could have something like this function

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and say it takes in an integer right.

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And if you define an integer mean say call it with the function pass in the X and say it's it's print.

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Ouch.

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Value x.

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It's here it's this.

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And we define the function down here.

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Say we can actually change the value right.

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If we wanted to know why it's us and we're in this C nothing surprising the value of y is gain and the

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value of x is 5.

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So we see that if we pass in the value of x into this function get change that value but it wouldn't

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change the original collar's variable at all.

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Right.

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So we're changing it to 15.

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But that doesn't affect X at all.

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And this is called pass by value.

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So we're just kind of copying the value into this function and just giving it in this case 5 say but

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actually have pointers here as are our parameters.

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Change it to be a pointer.

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Why do you take the address of X right.

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Because we have to pass in the address.

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This is remember that pointers taken addresses right.

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That's their values.

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And if we change all this what do you think the outcome should be.

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Let's try and see as your reference

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so you can see that the value of y is 15 and the value of x is 15.

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So what's going on.

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Well since we're passing the address of x K and again we're passing the address here we're changing

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x.

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This changes X because now y points to x.

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So why can change x's value right.

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So that's why it's changing here.

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So this is called passed by reference.

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So we're passing a reference to X's address here.

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OK.

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So this is one of the powerful features of pointers.

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This is why we use them so much as this is one of the good reasons for it.

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We can also do this with references to change this reference this.

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Now we don't need this right or that this k should see the same thing.

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Q Why is 15 in the value of X mean.

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Just so you totally believe me it's rere and this was a different value.

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Now it's 20 k so I'll often use references as per function parameters.

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Actually that's one of the primary uses I think of references is do you have it as a parameter.

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Often not for simple values like integers because usually you just want it to be just the value.

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So that's fine but later on you'll see that we really want to use references for a very specific reason.

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And I'll get into that in this in the future section.