使用型別實現單位系統
這個例子說明了 Go 的型別系統如何用於實現某些單元系統。
package main
import (
"fmt"
)
type MetersPerSecond float64
type KilometersPerHour float64
func (mps MetersPerSecond) toKilometersPerHour() KilometersPerHour {
return KilometersPerHour(mps * 3.6)
}
func (kmh KilometersPerHour) toMetersPerSecond() MetersPerSecond {
return MetersPerSecond(kmh / 3.6)
}
func main() {
var mps MetersPerSecond
mps = 12.5
kmh := mps.toKilometersPerHour()
mps2 := kmh.toMetersPerSecond()
fmt.Printf("%vmps = %vkmh = %vmps\n", mps, kmh, mps2)
}