Scheme for Java Programmer

String

>>>> in Java String st = new String("Seneca"); st = st.replace("e", "u"); System.out.println(st); // Sunuca

>>>> in Scheme (define st (java.lang.String'new "Seneca")) (set! st (st'replace "e" "u" )) (display st)  ; Sunuca

- - - - - - - - - - - - - - - - - - - - - - - - - - - - if

>>>> in Java int x = 3, y = 5, large = 0; if (x > y)

   large = x;

else

   large = y;

System.out.print(large); // 5

>>>> in Scheme (define x 3) (define y 5) (define large 0)

(if (> x y)

  (set! large x)
  (set! large y)

) (display large) ; 5

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>>>> in Java for (int i = 0; i < 10; i++)

   System.out.print(i);  // 0123456789

>>>> in Scheme (for ((i 0)) (< i 10) (set! i (+ i 1))

  (display i)  ; 0123456789

) - - - - - - - - - - - - - - - - - - - - - - - - - - - - While

>>>> in Java int n = 0; while(n < 10){

   System.out.print(n);
   n++;

} // 0123456789

>>>> in Scheme (define n 0)

(while (< n 10)

  (display n)
  (set! n (+ n 1))

)

0123456789

- - - - - - - - - - - - - - - - - - - - - - - - - - - - Switch Case

>>>> in Java int x = 7; String st = ""; switch (x){

   case 1: st = "one";    break;
   case 3: st = "three";  break;
   case 7: st = "seven";  break;
   default: st = "else";

} System.out.println(st);

>>>> in Scheme (define x 7) (define st "")

(case x

  ((1) (set! st 'one))
  ((3) (set! st 'three))
  ((7) (set! st 'seven))
  (else (set! st 'else))

)

(display st) ; seven

- - - - - - - - - - - - - - - - - - - - - - - - - - - - Iterator

>>>> in Java ArrayList numbers = new ArrayList();

for (int i = 0; i < 10; i++)

   numbers.add(i);

for (Iterator iterator = numbers.iterator(); iterator.hasNext();)

   System.out.print(iterator.next());    //  0123456789

>>>> in Scheme (import 'java.util.ArrayList) (define numbers (java.util.ArrayList'new))

(for ((i 0)) (< i 10) (set! i (+ i 1))

  (numbers'add i)

)

(for ((it (numbers'iterator))) (it'hasNext) ()

  (write (it'next)) ; 0123456789

)

- - - - - - - - - - - - - - - - - - - - - - - - - - - - Try and Catch

>>>> in Java

try {

   int x = 1 /0;

} catch (ArithmeticException e) {

   e.printStackTrace();

} finally{

   System.out.println("finally");

} // java.lang.ArithmeticException: / by zero // finally

>>>> in Scheme (try

  (define x (/ 1 0))
  (lambda (e) e)
  (display "finally")

)

final

#<java.lang.ArithmeticException

/ by zero>