Golang基础-Structs与Methods

• 将struct定义为一种类型Car
• NewCar函数return &Car{}，返回指针

// car.go
package elon

// Car implements a remote controlled car.
type Car struct {
	speed        int
	batteryDrain int

	battery  int
	distance int
}

// NewCar creates a new car with given specifications.
func NewCar(speed, batteryDrain int) *Car {
	return &Car{
		speed:        speed,
		batteryDrain: batteryDrain,
		battery:      100,
	}
}

• 给Car类型绑定方法
• 绑定方法到*Car，说明在指针上，函数内可以改变结构体的值；如果是Car，则是拷贝，不能改变原始变量的值。
• 给新的自定义类型绑定方法不一定要求类型是struct，也可以是int等一般类型。

package elon

import "fmt"

// TODO: define the 'Drive()' method
func (car *Car) Drive() {
	if car.battery < car.batteryDrain {
		return
	}
	car.distance += car.speed
	car.battery -= car.batteryDrain
}

// TODO: define the 'DisplayDistance() string' method
func (car *Car) DisplayDistance() string {
	return fmt.Sprintf("Driven %d meters", car.distance)
}

// TODO: define the 'DisplayBattery() string' method
func (car *Car) DisplayBattery() string {
	return fmt.Sprintf("Battery at %d%%", car.battery)
}

// TODO: define the 'CanFinish(trackDistance int) bool' method
func (car *Car) CanFinish(trackDistance int) bool {
	if (trackDistance+car.speed-1)/car.speed*car.batteryDrain > car.battery {
		return false
	} else {
		return true
	}
}