Continued fraction: Difference between revisions

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 Note that there are two kinds of continued fractions. The kind here where we alternate between '''a''' and '''b''' values, but in some other tasks '''b''' is always 1 (and not included in the list we use to represent the continued fraction). The other kind is evaluated in J using <code>(+%)/</code> instead of <code>+`%/</code>.
+=={{header|Icon}}==
+<syntaxhighlight lang="icon">
+$define EVAL_DEPTH 100
+# A generalized continued fraction, represented by two functions. Each
+# function maps from an index to a floating-point value.
+record continued_fraction (a, b)
+procedure main ()
+  local sqrt2_frac, e_frac, pi_frac
+  writes (" sqrt 2.0 = ")
+  write (evaluate_continued_fraction (continued_fraction (sqrt2_a, sqrt2_b),
+                                      EVAL_DEPTH))
+  writes ("        e = ")
+  write (evaluate_continued_fraction (continued_fraction (e_a, e_b),
+                                      EVAL_DEPTH))
+  writes ("       pi = ")
+  write (evaluate_continued_fraction (continued_fraction (pi_a, pi_b),
+                                      EVAL_DEPTH))
+end
+procedure evaluate_continued_fraction (frac, depth)
+  local i, retval
+  retval := frac.a (depth)
+  every i := depth to 1 by -1 do {
+    retval := frac.a (i - 1) + (frac.b (i) / retval)
+  }
+  return retval
+end
+procedure sqrt2_a (i)
+  return (if i = 0 then 1.0 else 2.0)
+end
+procedure sqrt2_b (i)
+  return 1.0
+end
+procedure e_a (i)
+  return (if i = 0 then 2.0 else real (i))
+end
+procedure e_b (i)
+  return (if i = 1 then 1.0 else real (i - 1))
+end
+procedure pi_a (i)
+  return (if i = 0 then 3.0 else 6.0)
+end
+procedure pi_b (i)
+  return real (((2 * i) - 1)^2)
+end
+</syntaxhighlight>
+{{out}}
+<pre>$ icon continued-fraction-task.icn
+ sqrt 2.0 = 1.414213562
+        e = 2.718281828
+       pi = 3.141592411
+</pre>
 =={{header|Java}}==