69 lines
1.4 KiB
Go
69 lines
1.4 KiB
Go
package converter
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import "errors"
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import "fmt"
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import "strconv"
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import "strings"
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const (
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markerMiles = "mi"
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markerKm = "km"
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markerFeet = "ft"
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markerMeter = "m"
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MilesToKm float64 = 1.609344
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FeetsToMeters float64 = 3.28084
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)
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var (
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inUnit string
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inVal float64
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asMeter float64
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err error
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convVal float64
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)
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func Convert(input, convTo string) (string, error) {
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switch {
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case strings.HasSuffix(input, markerKm):
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inUnit = markerKm
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case strings.HasSuffix(input, markerFeet):
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inUnit = markerFeet
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case strings.HasSuffix(input, markerMeter):
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inUnit = markerMeter
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case strings.HasSuffix(input, markerMiles):
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inUnit = markerMiles
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default:
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return "", errors.New("Invalid input: " + input)
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}
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inVal, err = strconv.ParseFloat(input[:len(input)-len(inUnit)], 64)
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if err != nil {
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return "", errors.New("Invalid input number (" + err.Error() + ")")
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}
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switch inUnit {
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case markerMiles:
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asMeter = inVal * MilesToKm * 1000
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case markerKm:
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asMeter = inVal * 1000
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case markerFeet:
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asMeter = inVal * FeetsToMeters
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case markerMeter:
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asMeter = inVal
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}
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switch convTo {
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case markerMiles:
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convVal = asMeter / (MilesToKm * 1000)
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case markerKm:
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convVal = asMeter / 1000
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case markerFeet:
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convVal = asMeter / FeetsToMeters
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case markerMeter:
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convVal = asMeter
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default:
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return "", errors.New("Invalid unit: " + convTo)
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}
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return fmt.Sprintf("%.2f%s", convVal, convTo), nil
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}
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