Add base 6 to base 16 converter

cmd/rand-convert/main.go

@@ -0,0 +1,57 @@
+package main
+
+import (
+	"fmt"
+	"math"
+	"math/rand"
+	"time"
+)
+
+// "given"
+func dice6() int {
+	return rand.Intn(6) + 1
+}
+
+// function specified by task "Seven-sided dice from five-sided dice"
+func dice16() (i int) {
+	for {
+		i = 6*dice6() - dice6()
+		if i < 32 {
+			break
+		}
+	}
+	return (i / 2) + 1
+}
+
+// function specified by task "Verify distribution uniformity/Naive"
+//
+// Parameter "f" is expected to return a random integer in the range 1..n.
+// (Values out of range will cause an unceremonious crash.)
+// "Max" is returned as an "indication of distribution achieved."
+// It is the maximum delta observed from the count representing a perfectly
+// uniform distribution.
+// Also returned is a boolean, true if "max" is less than threshold
+// parameter "delta."
+func distCheck(f func() int, n int,
+	repeats int, delta float64) (max float64, flatEnough bool) {
+	count := make([]int, n)
+	for i := 0; i < repeats; i++ {
+		count[f()-1]++
+	}
+	expected := float64(repeats) / float64(n)
+	for _, c := range count {
+		max = math.Max(max, math.Abs(float64(c)-expected))
+	}
+	fmt.Println(count)
+	return max, max < delta
+}
+
+// Driver, produces output satisfying both tasks.
+func main() {
+	rand.Seed(time.Now().UnixNano())
+	const calls = 1000000
+	max, flatEnough := distCheck(dice16, 16, calls, 500)
+	fmt.Println("Max delta:", max, "Flat enough:", flatEnough)
+	max, flatEnough = distCheck(dice16, 16, calls, 500)
+	fmt.Println("Max delta:", max, "Flat enough:", flatEnough)
+}