Question

所以我在查找3个数字之间的中间数字时遇到问题。我写了代码，但收到"Exception: Failure "int_of_string"消息。你知道为什么吗？

 let minimum a b c = min a (min b c)
 let maximum a b c = max a (max b c)
 let middle a b c =if a > (minimum a b c) && a < (maximum a b c) then Printf.printf "The middle is %d" a;
                    if b > (minimum a b c) && b < (maximum a b c) then Printf.printf "The middle is %d" b;
                    if c > (minimum a b c) && c < (maximum a b c) then Printf.printf "The middle is %d" c
let () = print_string "Enter x: "
let x = read_int ()
let () = print_string "Enter y: "
let y = read_int ()
let () = print_string "Enter z: "
let z = read_int ()
let mid = middle x y z;;

当我运行它时，我得到了：

let minimum a b c = min a (min b c)
let maximum a b c = max a (max b c)
let mediana a b c = if a > (minimum a b c) && a < (maximum a b c) then Printf.printf "The middle is %d" a;
                      if b > (minimum a b c) && b < (maximum a b c) then Printf.printf "The middle is %d" b;
                      if c > (minimum a b c) && c < (maximum a b c) then Printf.printf "The middle is %d" c
  let () = print_string "Enter x: "
  let x = read_int ()
  let () = print_string "Enter y: "
  let y = read_int ()
  let () = print_string "Enter z: "
  let z = read_int ()
  let mid = middle x y z;;
Enter x:
Exception: Failure "int_of_string".
#

Answer 1

如果我使用ocaml或utop命令从Linux shell启动全新的解释器，然后将您的第一个代码复制/粘贴到其中，那么输入该数字就没有问题。

但是，如果代码中;;后面有空白行，则ocaml解释器会将其视为x的输入，实际上直接抱怨空行不能转换为数字，导致出现您描述的症状。因此，我建议您在提供解释器时要小心，不要复制多余的字符（尤其是换行符），或切换到utop，这不会表现出这种现象，并且顶层更好，带有命令历史记录和自动补全功能。

找出3个数字的中间

1 个答案: