16_接口的继承.go
package main
import "fmt"
type Humaner interface {
//子集
sayhi()
}
type Personer interface {
//超集
Humaner //匿名字段,继承了sayhi()
sing(lrc string)
}
type Student struct {
name string
id int
}
//Student实现了sayhi()
func (tmp *Student) sayhi() {
fmt.Printf("Student[%s, %d] sayhi\n", tmp.name, tmp.id)
}
func (tmp *Student) sing(lrc string) {
fmt.Println("Student在唱着:", lrc)
}
func main() {
//定义一个接口类型的变量
var i Personer
s := &Student{"mike", 666}
i = s
i.sayhi() //继承过来的方法
i.sing("学生哥")
}
17_接口转换.go
package main
import "fmt"
type Humaner interface { //子集
sayhi()
}
type Personer interface { //超集
Humaner //匿名字段,继承了sayhi()
sing(lrc string)
}
type Student struct {
name string
id int
}
//Student实现了sayhi()
func (tmp *Student) sayhi() {
fmt.Printf("Student[%s, %d] sayhi\n", tmp.name, tmp.id)
}
func (tmp *Student) sing(lrc string) {
fmt.Println("Student在唱着:", lrc)
}
func main() {
//超集可以转换为子集,反过来不可以
var iPro Personer //超集
iPro = &Student{"mike", 666}
var i Humaner //子集
//iPro = i //err
i = iPro //可以,超集可以转换为子集
i.sayhi()
}
18_空接口.go
package main
import "fmt"
func xxx(arg ...interface{}) {
}
func main() {
//空接口万能类型,保存任意类型的值
var i interface{} = 1
fmt.Println("i = ", i)
i = "abc"
fmt.Println("i = ", i)
}
19_类型断言:if.go
package main
import "fmt"
type Student struct {
name string
id int
}
func main() {
i := make([]interface{}, 3)
i[0] = 1 //int
i[1] = "hello go" //string
i[2] = Student{"mike", 666} //Student
//类型查询,类型断言
//第一个返回下标,第二个返回下标对应的值, data分别是i[0], i[1], i[2]
for index, data := range i {
//第一个返回的是值,第二个返回判断结果的真假
if value, ok := data.(int); ok == true {
fmt.Printf("x[%d] 类型为int, 内容为%d\n", index, value)
} else if value, ok := data.(string); ok == true {
fmt.Printf("x[%d] 类型为string, 内容为%s\n", index, value)
} else if value, ok := data.(Student); ok == true {
fmt.Printf("x[%d] 类型为Student, 内容为name = %s, id = %d\n", index, value.name, value.id)
}
}
}
20_类型断言:switch.go
package main
import "fmt"
type Student struct {
name string
id int
}
func main() {
i := make([]interface{}, 3)
i[0] = 1 //int
i[1] = "hello go" //string
i[2] = Student{"mike", 666} //Student
//类型查询,类型断言
for index, data := range i {
switch value := data.(type) {
case int:
fmt.Printf("x[%d] 类型为int, 内容为%d\n", index, value)
case string:
fmt.Printf("x[%d] 类型为string, 内容为%s\n", index, value)
case Student:
fmt.Printf("x[%d] 类型为Student, 内容为name = %s, id = %d\n", index, value.name, value.id)
}
}
}
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