funcsPZ.go
func Pad(s, c string, n int) string {
	L := len(s)
	if L >= n {
		return s
	}
	n -= L

	left := strings.Repeat(c, int(math.Ceil(float64(n)/2)))
	right := strings.Repeat(c, int(math.Floor(float64(n)/2)))
	return left + s + right
}
func Pad(s, c string, n int) string {
	L := len(s)
	if L >= n {
		return s
	}
	n -= L

	left := strings.Repeat(c, int(math.Ceil(float64(n)/2)))
	right := strings.Repeat(c, int(math.Floor(float64(n)/2)))
	return left + s + right
}
// Pad pads string s on both sides with c until it has length of n.