package main
import (
"fmt"
"math"
)
type Abser interface {
Abs() float64
}
type MyFloat float64
func (f MyFloat) Abs() float64 {
if f < 0 {
return float64(-f)
}
return float64(f)
}
func main() {
var a Abser
f := MyFloat(-math.Sqrt2)
a = f // a MyFloat implements Abser
fmt.Println(a.Abs())
}
比如这段用 ruby 来打比方