import (
"fmt"
"os"
"time"
)
func timeCost() func(){
start:=time.Now()
return func(){
cost:=time.Since(start)
fmt.Printf("cost: %v",cost)
}
}
func main(){
//startT:=time.Now()
defer timeCost()()
s,sep:="",""
for _,arg := range os.Args[1:]{
s+=sep+arg
sep=" "
}
fmt.Println(s)
}