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In this lecture, we are going to learn how to create custom types with structures.

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We are going to be starting on a fresh project.

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I think the previous project was starting to get cluttered.

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I recommend moving into an empty directory when you're in an empty directory, initialize a new project

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by running the cargo net command.

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Next, let's open the main Port Arthur file.

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A structure can be thought of as a user defined type for grouping data.

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It's common for data to be grouped.

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For example, let's say we were creating a banking app.

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An account will hold various types of data, such as the owner's name, balance, interest rate, cetera.

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It's completely possible to avoid structures altogether.

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Theoretically, we can define variables for each of these values.

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However, if we need to create a new accounts, we will need to remember the values in an account by

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creating a structure.

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We can easily make sure every account has the same set of values.

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Rust enforces a strict model on structures.

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Let's take a closer look at structures by creating one at the top of the file.

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A structure can be defined by adding these struct keyword.

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Next, we need to give our structure a name.

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Let's give our structure the name of bank accounts.

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It's time to add fields into the mix.

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A field represents a single value in a structure.

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We can describe the makeup of structures with fields.

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The fields are in clothes with curly braces.

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The names for fields follow the same rules and conventions as variables.

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In addition, we must explicitly set the types of our fields.

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For this example, we will add two fields called balance and verified.

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The balance field will have an integer type.

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As for the verified field, it'll have a Boolean type.

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Our structure is ready.

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We have to find the data type, but we're not using it.

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If we want to create values with this structure, we can do so in a function inside.

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The main function will replace the existing code with a variable called my accounts.

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The value for this variable will be the bank account structure.

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Inside the curly braces, we must add the same fields defined in the bank account structure.

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This feature is one of the benefits of using a structure.

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We can hover our mouse over the structure to view the errors by the compiler.

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Our compiler is telling us we are missing two fields from the structure.

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It acts as a reminder whenever we're creating a new value with a structure.

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Let's add the balance and verified fields with random values.

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After adding these fields, the air should go away.

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Let's print the fields with the print line macro.

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We can access a specific field with dot notation.

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For example, let's try printing the balance field inside the print line macro.

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The string will contain a debug placeholder.

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For the second argument, we will pass in the my account balance field.

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Let's do the same for the verified field.

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Lastly, let's compile our project with the cargo run command.

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As you can see, we're able to access a field's value with dot notation, structures are very powerful

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because they allow us to group data.

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In addition, we benefit from its strictness.

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If we ever update a structure, our compiler will inform us of variables that aren't compliant with

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the structure.