Get all the primes within N

allprimes.go

package main

import (
    "fmt"
    "math"
    "sync"
)

var wg sync.WaitGroup

func isPrime(num int, primes chan<- int) {
    defer wg.Done()
    maxFactor := int(math.Sqrt(float64(num)))
    for i := 2; i <= maxFactor; i ++ {
        if num % i == 0 {
            return
        }
    }
    primes <- num
}

func main() {
    N := 100000
    primes := make(chan int, maxNum)
    for i := 1; i < N; i ++ {
        wg.Add(1)
        go isPrime(i, primes)
    }
    wg.Wait()
    close(primes)
    for p := range primes {
        fmt.Println(p)
    }
}