在其函数中调用函数时发生未定义的函数错误

Question

尝试在itelf中调用函数时出现未定义的函数错误。

我都测试了两个猜测，好吗？和猜测更好的seperatley，它们可以完美运行。然后我打电话给（square_root 1 2）尝试找到2的平方根。

;;;;program to find square root

(defun sqaure_root (guess x)
  (if (guess-okay? guess x)
      guess
    (square_root (better-guess guess x) x)))

(defun guess-okay? (guess x)
  "returns true if guess is within one 0.001 of value of square root"
  (> 0.001 (abs-x (- (square-x guess) x))))

(defun better-guess (guess x)
  "takes a guess and makes it a more accurate guess using newtons method of succsesive apporximations"
  (/ (+ guess (/ x guess)) 2))

错误是“未定义的函数square_root”，我不明白，因为我已经定义了它。我相信问题与在函数中调用函数有关，但我不确定。

Answer 1

正如其他人提到的，您有错误的函数定义。您的代码应如下所示：

;;;;program to find square root

(defun square_root (guess x)
  (if (guess-okay? guess x)
      guess
    (square_root (better-guess guess x) x)))

(defun guess-okay? (guess x)
  "returns true if guess is within one 0.001 of value of square root"
  (> 0.001 (abs-x (- (square-x guess) x))))

(defun better-guess (guess x)
  "takes a guess and makes it a more accurate guess using newtons method of succsesive apporximations"
  (/ (+ guess (/ x guess)) 2))

您在函数定义中拼写了“ square”，这就是为什么“ square_root”被视为未定义的原因。