Just another update

Task/Binary-search/CoffeeScript/binary-search-1.coffee

@@ -0,0 +1,8 @@
+binarySearch = (xs, x) ->
+  do recurse = (low = 0, high = xs.length - 1) ->
+    mid = Math.floor (low + high) / 2
+    switch
+      when high < low then NaN
+      when xs[mid] > x then recurse low, mid - 1
+      when xs[mid] < x then recurse mid + 1, high
+      else mid

Task/Binary-search/CoffeeScript/binary-search-2.coffee

@@ -0,0 +1,9 @@
+binarySearch = (xs, x) ->
+  [low, high] = [0, xs.length - 1]
+  while low <= high
+    mid = Math.floor (low + high) / 2
+    switch
+      when xs[mid] > x then high = mid - 1
+      when xs[mid] < x then low = mid + 1
+      else return mid
+  NaN

Task/Binary-search/CoffeeScript/binary-search-3.coffee

@@ -0,0 +1,8 @@
+do (n = 12) ->
+  odds = (it for it in [1..n] by 2)
+  result = (it for it in \
+    (binarySearch odds, it for it in [0..n]) \
+    when not isNaN it)
+  console.assert "#{result}" is "#{[0...odds.length]}"
+  console.log "#{odds} are odd natural numbers"
+  console.log "#{it} is ordinal of #{odds[it]}" for it in result

Task/Binary-search/CoffeeScript/binary-search.coffee

@@ -1,16 +0,0 @@
-binsearch = (arr, k) ->
-  low = 0
-  high = arr.length - 1
-  while low <= high
-    mid = Math.floor (low + high) / 2
-    return mid if arr[mid] == k
-    if arr[mid] < k
-      low = mid + 1
-    else
-      high = mid - 1
-  null
-
-arr = [1,3,5,7,9,11]
-for i in [0..12]
-  pos = binsearch arr, i
-  console.log "found #{i} at pos #{pos}" if pos?