GO语言学习笔记-接口2
传指针vs传值
上篇文章中所有接口实现我们都使用的传值，当然也可以使用传指针这种方式来实现接口。但使用传指针这种方式有一点需要注意，我们来看下面这个代码。
package main
import "fmt"
type Describer interface {
Describe()
}
type Person struct {
name string
age int
}
func (p Person) Describe() { //implemented using value receiver
fmt.Printf("%s is %d years old\n", p.name, p.age)
}
type Address struct {
state string
country string
}
func (a *Address) Describe() { //implemented using pointer receiver
fmt.Printf("State %s Country %s", a.state, a.country)
}
func main() {
var d1 Describer
p1 := Person{"Sam", 25}
d1 = p1
d1.Describe()
p2 := Person{"James", 32}
d1 = &p2
d1.Describe()
var d2 Describer
a := Address{"Washington", "USA"}
/* compilation error if the following line is
uncommented
cannot use a (type Address) as type Describer
in assignment: Address does not implement
Describer (Describe method has pointer
receiver)
*/
//d2 = a
d2 = &a //This works since Describer interface
//is implemented by Address pointer in line 22
d2.Describe()
}