package main

import "fmt"

type filterFunc func(n int) bool

func isEven(n int) bool { return n%2 == 0 }
func isOdd(m int) bool  { return m%2 == 1 }

func filter(f filterFunc, nums ...int) (filtered []int) {
	for _, n := range nums {
		if f(n) {
			filtered = append(filtered, n)
		}
	}
	return
}

func main() {
	nums := []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}

	fmt.Printf("evens      : %d\n", filter(isEven, nums...))
	fmt.Printf("odds       : %d\n", filter(isOdd, nums...))
}