球拍-UpperCase

Question

; defining the procedure char_toupper to convert a lower case character to upper case 
(define char_toupper (lambda (myChar) 
         ; defining x as the ASCII value of myChar 
         (define x (char->integer myChar)) 
         ; defining y as x-32 
         (define y (- x 32)) 
         ; if statement for while x is less than 91 (already uppercase) 
         (if (< x 91) 
          ; if it is already uppercase, just display it 
          (display myChar) 
          ; otherwise, if x is greater than 96 (lowercase) 
          (if (> x 96) 
           ; then display the character equivalent to the ASCII value given by y 
           (display (integer->char y)))))) 

(define string_toupper (lambda (myString newString i)  
         (if (< i (string-length myString)) 
          (string_toupper myString (string-append newString (char_toupper (string-ref myString i))) (+ 1 i))) 

         (display newString))) 
(string_toupper (read) "" 0) 

該轉換每個字符爲大寫，並進行顯示。但是我不斷收到錯誤，我可以找到它。任何幫助。謝謝

Answer 1

在球拍中，您必須編寫when而不是if在單臂的情況下。

即，在下面的表達式更改if到when。

(if (> x 96) 
    ; then display the character equivalent to the ASCII value given by y 
    (display (integer->char y))) 

另請注意，string-upcase是內置的。