pi.go

package main

import(
    "fmt"
    "math"
)

func main() {
    fmt.Printf("PI approx\n")
    piValue := float64(0)

    for i:=0; ;i++ {
        piValue += pi(i)
        if (i % 1e7 == 0) {
            fmt.Printf("%v\n", piValue)
        }
    }
}

func pi(k int) float64 {
    return 4 * (math.Pow(-1, float64(k)) / float64((2*k + 1)))
}