| package main | |
| import ( | |
| "fmt" | |
| "math" | |
| ) | |
| type Abser interface { | |
| Abs() float64 | |
| } | |
| func main() { | |
| var a Abser | |
| f := MyFloat(-math.Sqrt2) | |
| v := Vertex{3, 4} | |
| a = f // a MyFloat implements Abser | |
| a = &v // a *Vertex implements Abser | |
| a = v // a Vertex, does NOT | |
| // implement Abser | |
| fmt.Println(a.Abs()) | |
| } | |
| type MyFloat float64 | |
| func (f MyFloat) Abs() float64 { | |
| if f < 0 { | |
| return float64(-f) | |
| } | |
| return float64(f) | |
| } | |
| type Vertex struct { | |
| X, Y float64 | |
| } | |
| func (v *Vertex) Abs() float64 { | |
| return math.Sqrt(v.X*v.X + v.Y*v.Y) | |
| } |