64 lines
1.7 KiB
Go
64 lines
1.7 KiB
Go
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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"time"
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)
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const (
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randomMin = 0
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randomMax = 999999999999999999 // int64 max value is 9223372036854775807. We use one digit less than that with all 9's in order to not give bias to any digits.
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numSamples = 100000000 // A nice rounded human number
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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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for currentSample = 0; currentSample < numSamples; currentSample++ {
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results[firstDigit(rand.Intn(randomMax-randomMin+1)+randomMin)-1]++ // 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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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 (%f%%)\n", digitMinusOne+1, count, float64(count*100)/float64(numSamples))
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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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// firstDigit returns the first/leftmost digit of the base10 representation of an integer
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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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// numDigits returns the number of digits
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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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