Explain the use of Go's struct types for grouping and organizing data?

In Go, a struct is a composite data type that groups together zero or more values with different types. It is similar to a class in other object-oriented programming languages. Each value in a struct is called a field.

To define a struct type in Go, we use the **type** keyword followed by the name of the struct and the list of fields enclosed in curly braces. For example:

type Person struct {
    name string
    age  int
}

In this example, we have defined a struct type called **Person** with two fields: **name** of type **string** and **age** of type **int**.

We can create a new instance of the **Person** struct by using the Person type as a constructor function and providing values for its fields, like this:

p := Person{name: "John", age: 30}

We can access the fields of a struct using the dot notation, like this:

fmt.Println(p.name) // Output: John
fmt.Println(p.age)  // Output: 30

We can also create anonymous structs, which are structs without a defined type, like this:

p := struct {
    name string
    age  int
}{name: "John", age: 30}

Structs can also have methods associated with them, just like classes in other object-oriented programming languages. These methods are functions that have a receiver of the struct type, which means they can access and modify the fields of the struct. 

Here's an example:

func (p *Person) isAdult() bool {
    return p.age >= 18
}

fmt.Println(p.isAdult()) // Output: true

In this example, we have defined a method called **isAdult** on the **Person** struct, which returns a boolean indicating whether the person is an adult (i.e., 18 years or older). The **Person** syntax indicates that the method has a pointer receiver, which means it can modify the fields of the **Person** struct.