Generate primes using the Sieve of Eratosthenes

primes.go

package main

import (
	"fmt"
	"os"
	"strconv"
)

func main() {

	arg, _ := strconv.ParseInt(os.Args[1], 0, 0)
	input := int(arg)

	var primes []int
	takeout := make([]bool, input+1)

	// mark the multiples of half the slice as true
	for j := 2; j <= input/2; j++ {
		for k := 2; j*k <= input; k++ {
			takeout[j*k] = true
		}
	}

	// loop through the takeout slice and only print the indexes
	// where the value is false
	for e, v := range takeout {
		if v == false && e >= 2 {
			primes = append(primes, e)
		}
	}

	fmt.Printf("List of primes up to %d: %v\n", input, primes)
	if input == primes[len(primes)-1] {
		fmt.Printf("%d is prime\n", input)
	} else {
		fmt.Printf("%d is NOT prime\n", input)
	}

}