74 lines
1.6 KiB
Go
74 lines
1.6 KiB
Go
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package main
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import (
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"bufio"
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"fmt"
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"log"
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"math"
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"math/rand"
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"os"
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"runtime"
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"time"
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)
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const (
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randomMin = 0
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randomMax = 9999999999999999
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numSamples = 10000000
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)
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func main() {
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results := [9]int{} // There are 9 possible leading digits and 0 does not count, offset by 1 for index to actual value. Examples: To access 1 use [0]. To access 5 use [4]. To access 9 use [8].
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currentSample := 0
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statusTicker := time.NewTicker(time.Second)
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go func() {
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for {
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<-statusTicker.C
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percentCompleted := (currentSample * 100) / numSamples
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log.Printf("%d %% completed generating and analyzing samples", percentCompleted)
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}
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}()
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log.Printf("generating numbers...")
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rand.Seed(time.Now().UnixNano())
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generatedNumbers := make(chan int, 1024)
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for i := 0; i < runtime.NumCPU(); i++ {
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go generatorWorker(generatedNumbers)
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}
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for currentSample = 0; currentSample < numSamples; currentSample++ {
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results[firstDigit(<-generatedNumbers)-1]++
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}
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statusTicker.Stop()
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log.Printf("done.")
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// output results
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for digitMinusOne, count := range results {
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fmt.Printf("%d: %d\n", digitMinusOne+1, count)
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}
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fmt.Print("Press 'Enter' to continue...")
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bufio.NewReader(os.Stdin).ReadBytes('\n')
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}
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func generatorWorker(returnChannel chan int) {
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for {
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returnChannel <- rand.Intn(randomMax-randomMin+1) + randomMin // We must use Intn instead of Int because from Base10's perspective, integers cut off at a really weird spot
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}
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}
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func firstDigit(x int) int {
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return int(math.Abs(float64(x)) / math.Pow(10, float64(numDigits(x)-1)))
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}
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func numDigits(x int) int {
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if x == 0 {
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return 1
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}
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return int(math.Floor(math.Log10(math.Abs(float64(x))))) + 1
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}
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