[2019.03.08] Go lang (Struct)

Class가 없음 type struct 로 대체

- 키워드를 줄이기 위해서 용어를 하나로 통일한 듯

- 생성자도 자동으로 지원

- 메소드는 네임스페이스 방식처럼 알려줘서 지원함

package main

import "fmt"

type car struct {

    runTime uint16

    runSpeed uint16

}

func (carTemp car) calcRunningDistance() float64 {

    return float64(carTemp.runTime * carTemp.runSpeed)

}

func main() {

    carA := car{runTime: 100, runSpeed: 60}

    carB := car{runTime: 200}

    carC := car{100, 80}

    fmt.Println(carA.runTime)

    fmt.Println(carA.runSpeed)

    fmt.Println(carA.calcRunningDistance())

    fmt.Println(carB.runTime)

    fmt.Println(carB.runSpeed)

    fmt.Println(carB.calcRunningDistance())

    fmt.Println(carC.runTime)

    fmt.Println(carC.runSpeed)

    fmt.Println(carC.calcRunningDistance())

}

메소드 호출 방식이 Call by value 다.

매개변수 접근을 -> 로 안해서 좋다.

package main

import "fmt"

type car struct {

    runTime uint16

    runSpeed uint16

}

func (carTemp car) show() {

    fmt.Printf("%d %d\n", carTemp.runTime, carTemp.runSpeed)

}

func (carTemp car) swipeTimeAndSpeedByValue() {

    temp := carTemp.runTime

    carTemp.runTime = carTemp.runSpeed

    carTemp.runSpeed = temp

}

func (carTemp *car) swipeTimeAndSpeedByPointer() {

    temp := carTemp.runTime

    carTemp.runTime = carTemp.runSpeed

    carTemp.runSpeed = temp

}

func (carTemp *car) showPointerInMethod() {

    fmt.Println(carTemp)

    fmt.Println(*carTemp)

}

func main() {

    carA := car{runTime: 100, runSpeed: 60}

    carA.show()

    carA.swipeTimeAndSpeedByValue()

    carA.show()

    carA.swipeTimeAndSpeedByPointer()

    carA.show()

    carA.showPointerInMethod()

}

result

100 60

100 60

60 100

&{60 100}

{60 100}