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Struct embedding

Learn to embed one struct inside another.

Struct embedding

Go has no inheritance; instead a struct embeds another struct. The embedded struct's fields and methods become directly accessible through the outer struct:

type Kisi struct {
    Ad  string
    Yas int
}

type Calisan struct {
    Kisi          // no field name: embedded
    Departman string
}

c := Calisan{Kisi{"Ada", 36}, "Ar-Ge"}
fmt.Println(c.Ad, c.Departman)  // Ada Ar-Ge

Composition, not inheritance

Embedding isn't an "is-a" relationship but a "has-a" one: a Calisan can't be used where a Kisi value is expected. If fields share a name, the outer struct's field wins; the embedded one is reached through the full path. This clear rule avoids the complexity of deep inheritance hierarchies.

Practice Employee record

Write Kisi (Ad string, Yas int) and Calisan (Departman string), which embeds it. Create c := Calisan{Kisi{"Ada", 36}, "Ar-Ge"}, do c.Yas++ and print c.Ad, c.Yas and c.Departman.

Starter code

main.go
package main

import "fmt"

func main() {
    // buraya yaz
}

Sample solution

main.go
package main

import "fmt"

type Kisi struct {
    Ad  string
    Yas int
}

type Calisan struct {
    Kisi
    Departman string
}

func main() {
    c := Calisan{Kisi{"Ada", 36}, "Ar-Ge"}
    c.Yas++
    fmt.Println(c.Ad, c.Yas, c.Departman)
}

Expected output

Ada 37 Ar-Ge

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 What is the difference between <code>c.Ad</code> and <code>c.Kisi.Ad</code>?

  • c.Ad returns empty
  • None; c.Ad is shorthand for c.Kisi.Ad Correct answer
  • c.Ad is a copy
  • c.Kisi.Ad doesn't compile

Explanation: Embedded fields are "promoted"; the full path c.Kisi.Ad is always valid too.

2 Embedded field

Question 
type Ogretmen struct {
    ____
    Brans string
}
Answer 
type Ogretmen struct {
    Kisi
    Brans string
}

Explanation: Writing just the type name, without a field name, embeds the struct.

3 Concept

Term Meaning
Embedding Has-a relationship
c.Ad Promoted field
c.Kisi.Ad Full path
Inheritance Not in Go

All lessons in Beginner

1 Go basics

  1. What is Go?
  2. Installing Go
  3. Your first program
  4. go run and go build
  5. Comments and semicolons
  6. Summary - Go basics

2 Modules

  1. go mod init
  2. package and import
  3. The main package
  4. Multiple files
  5. go.sum and dependencies
  6. Summary - Modules

3 Variables

  1. Declaration with var
  2. Short declaration :=
  3. const and iota
  4. Zero value
  5. Type inference
  6. Summary - Variables

4 Data types

  1. int and float
  2. bool and string
  3. byte and rune
  4. Type conversion
  5. Type definitions
  6. Summary - Data types

5 Project: Calculator

  1. Project design
  2. Add and subtract
  3. Multiply and divide
  4. Command-line menu

6 Functions

  1. func declaration
  2. Parameters and return
  3. Multiple return
  4. Variadic functions
  5. Anonymous functions
  6. Summary - Functions

7 Control flow

  1. if, else if, else
  2. for loop
  3. Iterating with range
  4. switch and fallthrough
  5. break and continue
  6. Summary - Control flow

8 Array and slice

  1. Array declaration
  2. Slice declaration
  3. Appending with append
  4. Sub-slice
  5. len and cap
  6. Summary - Array and slice

9 Project: Shopping cart

  1. Product struct
  2. Adding to cart
  3. Computing total
  4. Printing the cart

10 Map

  1. Map declaration
  2. Adding elements
  3. Looking up in a map
  4. Deleting from a map
  5. Iterating a map with range
  6. Summary - Map

11 String

  1. String and byte
  2. String concatenation
  3. Conversion with strconv
  4. The strings package
  5. Rune and UTF-8
  6. Summary - String

12 Pointer

  1. What is a pointer?
  2. & and * operators
  3. The new function
  4. Pointers and functions
  5. Nil pointer
  6. Summary - Pointer

13 Struct

  1. Struct declaration
  2. Creating a struct
  3. Field access
  4. Struct embedding
  5. Struct and pointer
  6. Summary - Struct

14 Methods

  1. Method declaration
  2. Pointer receiver
  3. Value receiver
  4. Methods and embedding
  5. Method chaining
  6. Summary - Methods

15 Interface and error

  1. Interface declaration
  2. Implicit satisfaction
  3. The error interface
  4. Returning errors
  5. errors.Is and errors.As
  6. Summary - Interface and error

16 Beginner final

  1. Challenge 1 - Combined program
  2. Challenge 2 - Data structure
  3. Challenge 3 - Error handling
  4. Challenge 4 - Mini app