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@kjk
Last active Nov 5, 2019
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Interfaces
// :collection Essential Go
package main
import (
"fmt"
"strconv"
)
// :show start
// Stringer is an interface with a single method
type Stringer interface {
String() string
}
// User struct that implements Stringer interface
type User struct {
Name string
}
func (u *User) String() string {
return u.Name
}
// Any type can implement an interface. Here we create
// an alias of int type an implement Stringer interface
type MyInt int
func (mi MyInt) String() string {
return strconv.Itoa(int(mi))
}
// printTypeAndString accepts an interface. 's' can be any value
// that implements Stringer interface
func printTypeAndString(s Stringer) {
fmt.Printf("%T: %s\n", s, s)
}
func main() {
u := &User{Name: "John"}
printTypeAndString(u)
n := MyInt(5)
printTypeAndString(n)
}
// :show end
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