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What is the principle of field access when structure nesting in Go language

In Go, a struct is an aggregated data type that can contain multiple different data types, including other structs. When you nest another structure in one structure, you can access the fields of the nested structure just like you would access the normal fields.

Steps to access fields when structure nesting

1. Definition Structure: First, you need to define two or more structure types. One of the structures may contain another structure as its field.

2. Create instance: You can then create an instance containing a nested structure.

3. Access Field: To access the fields of a nested structure, you need to gradually access the fields of the nested structure through an instance of the external structure. This is usually achieved through chain access (dot operator .).

Sample Code

type Inner struct {
    A int
}

type Outer struct {
    Inner Inner
}

// Suppose there is a variable outer of type Outer
var outer Outer
// Access field A in the Inner structure
fmt.Println(outer.Inner.A)

Here, outer is an instance of the Outer type, Inner is a field in the Outer structure, which itself is an instance of the Inner type, and A is a field in the Inner structure. With the dot operator ., you can access fields from one struct instance, even if they are nested.

Summarize

The principle of field access when structs are nested is to access the fields of nested structures in a chain through the point operator ., which allows you to access nested structure fields of any depth.