14、组合与转发-GOLANG

合并结构

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package main

import "fmt"

//	type report struct {
//		sol       int
//		high, low float64 //当我们需要更多的数据时这种写法显得不够灵活，这里的high和low也不好根据含义判断
//		lat, long float64
//	}
type temperature struct {
	high, low float64 //在这里我们根据结构名一眼dingzhen，鉴定high,low为温度
}
type location struct {
	lat, long float64
}
type report struct {
	sol      int
	tem      temperature //在结构中插入其他的结构类型，当小的结构类型需要调整时对大结构的影响相对较小
	location location
}

func main() {
	boadbury := location{-14.5684, 175.472636}
	tem := temperature{high: -1.0, low: -78.0}
	report := report{15, tem, boadbury}
	fmt.Println(report)
}

为温度结构编辑方法实现计算平均温度

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package main

import "fmt"

type temperature struct {
	high, low celsius
}
type location struct {
	lat, long float64
}
type report struct {
	sol      int
	tem      temperature
	location location
}
type celsius float64

func (t temperature) average() celsius {
	return (t.high + t.low) / 2
}
func main() {
	//tem := temperature{high: -1.0, low: -78.0}
	//fmt.Println("平均温度为", tem.average())//多种调用方式
	boadbury := location{-14.5684, 175.472636}
	tem := temperature{high: -1.0, low: -78.0}
	report := report{15, tem, boadbury}

	fmt.Println("平均温度为", report.tem.average())
}


为report类型编写直接访问平均温度的方法

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package main

import "fmt"

type temperature struct {
	high, low celsius
}
type location struct {
	lat, long float64
}
type report struct {
	sol      int
	tem      temperature
	location location
}
type celsius float64

func (t temperature) average() celsius {
	return (t.high + t.low) / 2
}
func (r report) average() celsius {//同名函数，留个坑
	return r.tem.average()
}
func main() {

	boadbury := location{-14.5684, 175.472636}
	tem1 := temperature{high: -1.0, low: -78.0}
	report1 := report{15, tem1, boadbury}

	fmt.Println("平均温度为", report1.average())
}

自动转发方法

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package main

import "fmt"

type temperature struct {
	high, low celsius
}
type location struct {
	lat, long float64
}
type report struct {
	sol         int
	temperature //不指定字段名，嵌入类型，go语言会将temperature类型所有方法自动为report所用
	location
}
type celsius float64

func (t temperature) average() celsius {
	return (t.high + t.low) / 2
}

func main() {

	boadbury := location{-14.5684, 175.472636}
	tem1 := temperature{high: -1.0, low: -78.0} //结构会自动为被嵌入的类型生成同名字段
	report1 := report{15, tem1, boadbury}

	fmt.Println("平均温度为", report1.average())
	fmt.Println("最高温度为", report1.high) //还可以通过report类型的变量直接访问temperature的属性

}

命名冲突

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package main

type sol int
type celsius float64
type temperature struct {
	high, low celsius
}
type location struct {
	lat, long float64
}
type report struct {
	sol
	temperature
	location
}

func (s sol) days(s2 sol) int {
	days := int(s2 - s)
	if days < 0 {
		days = -days
	}
	return days
}
func (l location) days(l2 location) int {
	return 5
}
func main() {
	boadbury := location{-14.5684, 175.472636}
	tem1 := temperature{high: -1.0, low: -78.0}
	report1 := report{15, tem1, boadbury}
	d:=report1.days(1466)//在这个地方的调用会报错，解决方法在上面我们其实也用过，那就是给report也生命一个同名方法该方法优先级要高
}

ambiguous:有歧义的

image-20230311085723878

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package main

import "fmt"

type sol int
type celsius float64
type temperature struct {
	high, low celsius
}
type location struct {
	lat, long float64
}
type report struct {
	sol
	temperature
	location
}

func (s sol) days(s2 sol) int {
	days := int(s2 - s)
	if days < 0 {
		days = -days
	}
	return days
}
func (l location) days(l2 location) int {
	return 5
}
func (r report) days(s sol) int {//优先级最高的days方法，当我们需要另一个类型的days方法时只需要手动修改这里就行
	return r.sol.days(s)
}
func main() {
	boadbury := location{-14.5684, 175.472636}
	tem1 := temperature{high: -1.0, low: -78.0}
	report1 := report{15, tem1, boadbury}
	d := report1.days(1466)
	fmt.Println(d)
}