Map range: Difference between revisions
Go solution
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Line 242:
end function Maprange
end program Map</lang>
=={{header|Go}}==
For the extra credit, ", ok" is a Go idiom. It takes advantage of Go's multiple return values feature to return a success/failure disposition. In the case of this task, the result t is undefined if the input s is out of range.
<lang go>package main
import "fmt"
// assumes a1 < a2
func newRangeMap(a1, a2, b1, b2 float64) func(float64) (float64, bool) {
return func(s float64) (t float64, ok bool) {
if s < a1 || s > a2 {
return 0, false // out of range
}
return b1 + (s-a1)*(b2-b1)/(a2-a1), true
}
}
func main() {
rm := newRangeMap(0, 10, -1, 0)
for s := float64(-2); s <= 12; s += 2 {
t, ok := rm(s)
if ok {
fmt.Printf("s: %5.2f t: %5.2f\n", s, t)
} else {
fmt.Printf("s: %5.2f out of range\n", s)
}
}
}</lang>
Output:
<pre>
s: -2.00 out of range
s: 0.00 t: -1.00
s: 2.00 t: -0.80
s: 4.00 t: -0.60
s: 6.00 t: -0.40
s: 8.00 t: -0.20
s: 10.00 t: 0.00
s: 12.00 out of range
</pre>
=={{header|J}}==
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