我在康奈尔大学课程中使用下面的代码求平方根,但是代码返回错误的值,代码是
fun squareRoot(x: real): real =
let
val delta = 0.0001
fun goodEnough(guess: real): bool =
if(abs(guess*guess - x) < delta) then true else false
fun improve(guess: real): real =
(guess + x/guess) / 2.0
fun tryGuess(guess: real): real =
if goodEnough(guess) then guess
else tryGuess(improve(guess))
in
tryGuess(1.0)
end
执行时
use "squareroot1.sml";
[opening squareroot1.sml]
val squareRoot = fn : real -> real
val it = () : unit
- squareroot 9.0;
val it = 1.0 : real
-
它总是返回 1.0 作为根,你能告诉为什么会这样吗?