value of pi

value_of_pi.go

package main

import (
  "fmt"
  "math/rand"
  "time"
)

func main() {
  rand.Seed(time.Now().UnixNano())
  var sum int64 = 0
  var i int64 = 0
  var tot int64 = 10 * 1000 * 1_000_000
  start := time.Now() 
  for {
    x := rand.Float64() * 2 - 1
    y := rand.Float64() * 2 - 1
    d := x*x + y*y
    if d <= 1 {
      sum += 1
    }
    i += 1
    if i >= tot {
      break
    }
  }
  var pi float64 = (4.0 * float64(sum)) / (float64(tot - 1) * 1.0)
  dur := time.Since(start)
  fmt.Printf("value of pi %f calculated in %d ms with %d iterations", pi, dur.Milliseconds(), tot)
}