 Hey everybody, it's Brian. This is our eighth C++ video. I'm going to be discussing type definitions or type def. What is type def? Alright, let's say we want an unsigned short int, and we'll call it h, zero. Well, as we know, that means it cannot be negative. It is a short integer or very small integer initialized to zero. As you can see, it will run perfectly fine. I mean, we've typed it correctly. So, what's a type def? Well, let's imagine you want a couple of these. Got a little ahead of myself here, and we'll just call it a, b, c, and you guessed it, d. Well, that's a lot of copying and pasting. Now let's say we want to go back later and we want to get rid of the unsigned because we want to make these negatives. Well then we've got to go back and delete unsigned out of each one of these. There's a simpler way, and I'm going to show it to you. It's called type def. Type def. Now type def is short for type definition. Type def, and then you give it the type, and then a name. And we'll call it u short. Now what we're doing is we're creating an alias. So we're saying u short is an unsigned short int. So we can actually replace all of these with u short. And any pre, or any additional ones we want to create, but you can just type u short. So it's much cleaner, much easier to read, but you would have to memorize what this means. Now why would you use type def? Well, like I said, if you had say 100 of these variables and you wanted to go and get rid of the unsigned, you'd have to go in and delete unsigned out of each one of those now. I'm sure you could refract your code, but you know, what if there's other variables that you need unsigned? Well, that can get tedious and now you're manually going through your code. Let's compile this just to show you that it runs. So if you wanted to make that change with type def, you would just delete it out of the definition. It still compiles. Very quick and easy. Nice way of changing your variable types. This is Brian. I hope you found this video educational and entertaining, and thank you for watching.