itoa可以套公式，下面的依旧会按照公式运算
package main
import "fmt"
func main() {
const (
b = 1 << (10 * iota)
kb
mb
tb
pb
)
fmt.Println(b, kb, mb, tb, pb) //1 1024 1048576 1073741824 1099511627776
}
package main
impor
