March 2014 update

Task/Jensens-Device/Forth/jensens-device-1.fth

@@ -1,3 +1,2 @@
-: s>f s>d d>f ;
 : sum 0 s>f 1+ swap ?do i over execute f+ loop drop ;
 :noname s>f 1 s>f fswap f/ ; 1 100 sum f.

Task/Jensens-Device/Forth/jensens-device-2.fth

@@ -0,0 +1,6 @@
+fvariable ii \ i is a Forth word that we need
+: sum ( xt1 lo hi xt2 -- r )
+  0e swap 1+ rot ?do ( addr xt r1 )
+    i s>f over execute f! dup execute f+
+  loop 2drop ;
+' ii 1 100 :noname 1e ii f@ f/ ; sum f.

Task/Jensens-Device/Java/jensens-device-1.java

@@ -0,0 +1,12 @@
+import java.util.function.*;
+import java.util.stream.*;
+
+public class Jensen {
+    static double sum(int lo, int hi, IntToDoubleFunction f) {
+        return IntStream.rangeClosed(lo, hi).mapToDouble(f).sum();
+    }
+
+    public static void main(String args[]) {
+        System.out.println(sum(1, 100, (i -> 1.0/i)));
+    }
+}

Task/Jensens-Device/Java/jensens-device-2.java

@@ -0,0 +1,21 @@
+public class Jensen2 {
+
+    interface IntToDoubleFunction {
+        double apply(int n);
+    }
+
+    static double sum(int lo, int hi, IntToDoubleFunction f) {
+        double res = 0;
+        for (int i = lo; i <= hi; i++)
+            res += f.apply(i);
+        return res;
+
+    }
+    public static void main(String args[]) {
+        System.out.println(
+            sum(1, 100,
+                new IntToDoubleFunction() {
+                    public double apply(int i) { return 1.0/i;}
+                }));
+    }
+}