Go/Structs

Lesson 8 of 8

Structs Cheatsheet

Basic Definition

type User struct {
    Name string
    Age  int
}

Instantiation

u := User{Name: "Bob", Age: 30}
u.Name = "Alice" // Dot operator

Advanced Types

  • Nested: type A struct { b B } -> a.b.field
  • Embedded: type A struct { B } -> a.field (Field promotion)
  • Anonymous: val := struct{ x int }{ x: 10 }
  • Empty: struct{}{} (Zero bytes)

Methods

func (u User) Greet() string {
    return "Hello " + u.Name
}

Memory Optimization

  • Fields are contiguous.
  • Ordering from largest to smallest reduces padding.
  • Use reflect.TypeOf(s{}).Size() to check memory usage.

Key Concepts

  • Structs are the primary way to group related data.
  • Dot operator . is used for all field and method access.
  • Embedded structs allow for a form of composition/inheritance.