哪位大侠知道？
1# llh_xmu

fun <- function() {
  ANSWER <- readline("Are you a satisfied R user? ")
  ## a better version would check the answer less cursorily, and
  ## perhaps re-prompt
  if (grepl("no",ANSWER)
    cat("This is impossible.  YOU LIED!\n")
  else
    cat("I knew it.\n")
}
if(interactive()) fun()