package Lib import ( "fmt" "math/rand" "strings" "time" ) func SmsCode(width int) string { numeric := [10]byte{0,1,2,3,4,5,6,7,8,9} r := len(numeric) rand.Seed(time.Now().UnixNano()) var sb strings.Builder for i := 0; i < width; i++ { fmt.Fprintf(&sb, "%d", numeric[ rand.Intn(r) ]) } return sb.String() }