rand7_from_rand5_test.go

package rand7

import (
	"math/rand"
	"testing"
)

func rand5() int {
	return rand.Intn(5) + 1
}

func rand7() int {
	num := 0
	for i := 0; i < 7; i++ {
		num += rand5() * i
	}
	return int(num % 7)
}

func TestRand7(t *testing.T) {
	const N = 1000000
	counts := map[int]int{}
	for i := 0; i < N; i++ {
		counts[rand7()]++
	}

	for i := 1; i < 7; i++ {
		println(i, counts[i])
	}

	/*
		OUTPUT:
		1 142200
		2 142559
		3 142895
		4 142930
		5 143328
		6 143498
	*/

  t.Error("stop the show! :D")
}