path: courses/go-course/struct-go.md

- **fileName**: struct-go
- **Created on**: 2024-08-26 16:51:12

struct in go is using to makeing a types from main types and struct and etc....

example:

type car struct {
  make string
  model string
  doors int
  mileage int
}

nested struct example:

type wheel struct {
  radius int
  material strin
}
type car struct {
  mileage int
  frontWheel wheel
}
// using struct 
myCar := car{}
myCar.frontWheel.radius = 5

another example about how to use struct example:

type user struct {
    username string
    lastname string
    age int
    UserWork work
}
type work struct {
    salirary int
    department string
}
func main() {
    us1 := user{"yossef", "sabry", 20, work{2000, "it"}}
    fmt.Printf("the user name is %s %s, and age %d\n", us1.username, us1.lastname, us1.age)
    fmt.Printf("user work is %s, and salirary %d", us1.UserWork.department, us1.UserWork.salirary)
    return
}

# Anonymous Structs in Go Example:

myCar := struct {
  make string
  model string
} {
  make: "tesla",
  model: "model 3",
}

- is using for make a struct for using only one time not any one can used it again

another way to write Anonymous structs

type car struct {
  make string
  model string
  doors int
  mileage int
  // wheel is a field containing an anonymous struct
  wheel struct {
    radius int
    material string
  }
}

embedded struct example:

type car struct {
  make string
  model string
}

type truck struct {
  // "car" is embedded, so the definition of a
  // "truck" now also additionally contains all
  // of the fields of the car struct
  car
  bedSize int
}
/*
type truck struct {
  make string
  model string
  bedSize int
} //now this the look for using this struct
*/

Embedded vs nested

- Unlike nested structs, an embedded struct's fields are accessed at the top level like normal fields.
- Like nested structs, you assign the promoted fields with the embedded struct in a composite literal.

lanesTruck := truck{
  bedSize: 10,
  car: car{
    make: "toyota",
    model: "camry",
  },
}

fmt.Println(lanesTruck.bedSize)

// embedded fields promoted to the top-level
// instead of lanesTruck.car.make
fmt.Println(lanesTruck.make)
fmt.Println(lanesTruck.model)

Struct methods in Go

type rect struct {
width int
height int
}
// area has a receiver of (r rect)
// rect is the struct
// r is the placeholder
func (r rect) area() int {
return r.width * r.height
}
var r = rect{
width: 5,
height: 10,
}
fmt.Println(r.area())
// prints 50

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