Lisp 试图计算工资总额

我正在尝试创建一个程序，计算员工每周的总工资

这是我的密码

(princ"Enter working hours: ")
(defparameter workhours(read))
(if (and (>= workhours 0)) (<= workhours 60))
    (princ"Enter hourly pay rate: ")
    (defparameter HPrate(read))
    (if(<= workhours 40)
        (* workhours HPrate))

---

您应该尝试将代码的逻辑与输入/输出操作（如询问数字或编写结果）分开。通常最好只编写给定数字和输出数字的函数。然后，您可以从任何类型的用户界面（图形或文本）调用它

业务逻辑 您需要计算给定工作小时数和小时工资的总工资

因此，您定义了一个名为

毛工资

的函数，该函数将

工时数

和

小时工资

作为输入：

(defun gross-pay (work-hours hourly-rate)
  10000 ;; a lot of money, just for testing
  )

现在定义了它，您可以调用它，您的环境将自动打印结果：

* (gross-pay 0 0)
10000 

代码中的一个问题是，

if

分支包含一个测试和三个分支，这不是有效的语法。根据你所写的，我猜你想有这样的逻辑：

(defun gross-pay (work-hours hourly-rate)
  (assert (<= 0 work-hours 60))
  ;; ...
  )

通过使用

多值绑定

，可以获得多个

值的结果，如下所示：

(defun gross-pay (work-hours hourly-rate)
  (assert (<= 0 work-hours 60))
  (multiple-value-bind (regular overtime) (split-time work-hours)
    ;; here regular and overtime are bound to values
    ))

输入/输出
如果需要，可以在命令行界面中包装逻辑：

(defun gross-pay/io ()
  (gross-pay
   (ask "Enter working hours: " '(integer 0 60))
   (ask "Enter hourly pay rate: " '(integer 1 1000))))

上述功能的实现多亏了这个helper函数，它负责处理请求输入时可能出现的不同问题（清除缓冲、强制输出、读取值时禁用求值、检查类型等）

在我的环境中，以下是一个示例交互：

USER> (gross-pay/io)

Enter working hours: 5

Enter hourly pay rate: 3

15

还有一个输入错误的例子：

Enter working hours: 87
type mismatch: 87 not of type (INTEGER 0 60)
Enter working hours: ""
type mismatch:  not of type (INTEGER 0 60)
Enter working hours: 15

Enter hourly pay rate: 0
type mismatch: 0 not of type (INTEGER 1 1000)
Enter hourly pay rate: 88

1320

***-（我不认识这个语法“***-”你的Lisp环境是什么？工作时间的值是什么？顺便说一下，断言告诉你表达式是错误的(
* (gross-pay 10 1)
10

* (= (gross-pay 50 1)
     (+ (* 40 1) 
        (* 10 3/2)))
T

(defun gross-pay/io ()
  (gross-pay
   (ask "Enter working hours: " '(integer 0 60))
   (ask "Enter hourly pay rate: " '(integer 1 1000))))

(defun ask (prompt type)
  (let ((*standard-output* *query-io*))
    (loop
      (clear-input)
      (fresh-line)
      (princ prompt)
      (finish-output)
      (let ((value (let ((*read-eval* nil)) (read))))
        (if (typep value type)
            (return value)
            (format *error-output*
                    "type mismatch: ~a not of type ~a"
                    value type))))))

USER> (gross-pay/io)

Enter working hours: 5

Enter hourly pay rate: 3

15

Enter working hours: 87
type mismatch: 87 not of type (INTEGER 0 60)
Enter working hours: ""
type mismatch:  not of type (INTEGER 0 60)
Enter working hours: 15

Enter hourly pay rate: 0
type mismatch: 0 not of type (INTEGER 1 1000)
Enter hourly pay rate: 88

1320