Struct

Search…
Struct
A struct is a composite data type (or record) declaration that defines a physically grouped list of variables under one name in a block of memory, allowing different variables to be accessed via a single pointer or by the struct declared name which returns the same address.
For people coming from OOP languages, it can be thought as class but with more restrictions.
1
struct User {
2
    name string
3
    email string
4
    country string
5
}
6
​
7
fn main() {
8
    user := User {
9
        name: "V developers"
10
        email: "[email protected]"
11
        country: "Canada"
12
    }
13
​
14
    println(user.country)
15
}
Copied!
Note: Structs are allocated on the stack.
You can use a comma to separate each field when creating a new instance of the struct. It's useful when you want to create a new instance on a single line.
1
user := User { name: "V developers", email: "[email protected]", country: "Canada" }
Copied!
The & prefix
You can allocate a struct on the heap and get a reference to it by using the & prefix as follows:
1
user := &User{"V developers", "[email protected]", "Canada"}
2
println(user.name)
Copied!
The type of user is &User. It's a reference to User.
Access modifiers
Struct fields are private and immutable by default. Their access modifiers can be changed with pub and mut.
1
struct User {
2
    email string
3
}
Copied!
You can define them as private mutable.
1
struct User {
2
    email string
3
mut:
4
    first_name string
5
    last_name string
6
}
Copied!
You can also define them as public immmutable (readonly).
1
struct User {
2
    email string
3
mut:
4
    first_name string
5
    last_name string
6
pub:
7
    sin_number int
8
}
Copied!
or as public, but mutable only in the parent module.
1
struct User {
2
   email string
3
mut:
4
   first_name string
5
   last_name string
6
pub:
7
   sin_number int
8
pub mut:
9
   phone int
10
}
Copied!
or public and mutable both inside and outside parent module.
1
struct User {
2
    email string
3
mut:
4
    first_name string
5
    last_name string
6
pub:
7
    sin_number int
8
pub mut:
9
    phone int
10
pub mut mut:
11
    address_1 string
12
    address_2 string
13
    city string
14
    country string
15
    zip     string
16
}
Copied!
Exercises
1.Create a struct that stores and displays User information.
2.Create a Point struct that holds x and y field and guard them with private and public.
Arrays
section_1
Last modified 2yr ago
Copy link
Contents
The & prefix
Access modifiers
Exercises