Another update from ingydotnet^djgoku

Task/Sorting-algorithms-Cocktail-sort/Eiffel/sorting-algorithms-cocktail-sort-1.e

@@ -1,50 +1,90 @@
 class
-	COCKTAIL_SORT[G -> COMPARABLE]
+	COCKTAIL_SORT [G -> COMPARABLE]
+
 feature
-cocktail_sort(ar: ARRAY[G]): ARRAY[G]
-	require
-		ar_not_empty: ar.count>=1
-	local
-		swapped, finished: BOOLEAN
-		sol: ARRAY[G]
-		i,j : INTEGER
-		t: G
-	do
-		create sol.make_from_array (ar)
-		from
-		until finished= TRUE
-		loop
-		swapped := FALSE
-		from
-			i:= 1
-		until
-			i= ar.count-1
-		loop
-			if ar[i]> ar[i+1]		then
-				t:= ar[i]
-				ar[i]:= ar[i+1]
-				ar[i+1]:= t
-				swapped:= true
+
+	cocktail_sort (ar: ARRAY [G]): ARRAY [G]
+			-- Array sorted in ascending order.
+		require
+			ar_not_empty: ar.count >= 1
+		local
+			not_swapped: BOOLEAN
+			sol: ARRAY [G]
+			i, j: INTEGER
+			t: G
+		do
+			create Result.make_empty
+			Result.deep_copy (ar)
+			from
+			until
+				not_swapped = True
+			loop
+				not_swapped := True
+				from
+					i := Result.lower
+				until
+					i = Result.upper - 1
+				loop
+					if Result [i] > Result [i + 1] then
+						Result := swap (Result, i)
+						not_swapped := False
+					end
+					i := i + 1
+				end
+				from
+					j := Result.upper - 1
+				until
+					j = Result.lower
+				loop
+					if Result [j] > Result [j + 1] then
+						Result := swap (Result, j)
+						not_swapped := False
+					end
+					j := j - 1
+				end
 			end
-			i:= i+1
+		ensure
+			ar_is_sorted: is_sorted (Result)
 		end
 
-		from j:= ar.count-1
-		until j= 1
-		loop
-		if ar[j]> ar[j+1] then
-			t:= ar[j]
-			ar[j]:= ar[j+1]
-			ar[j+1]:= t
-			swapped:= TRUE
+feature{NONE}
+
+	swap (ar: ARRAY [G]; i: INTEGER): ARRAY [G]
+			-- Array with elements i and i+1 swapped.
+		require
+			ar_not_void: ar /= Void
+			i_is_in_bounds: ar.valid_index (i)
+		local
+			t: G
+		do
+			create Result.make_empty
+			Result.deep_copy (ar)
+			t := Result [i]
+			Result [i] := Result [i + 1]
+			Result [i + 1] := t
+		ensure
+			swapped_right: Result [i + 1] = ar [i]
+			swapped_left: Result [i] = ar [i + 1]
 		end
-		j:= j-1
+
+	is_sorted (ar: ARRAY [G]): BOOLEAN
+			--- Is 'ar' sorted in ascending order?
+		require
+			ar_not_empty: ar.is_empty = False
+		local
+			i: INTEGER
+		do
+			Result := True
+			from
+				i := ar.lower
+			until
+				i = ar.upper
+			loop
+				if ar [i] > ar [i + 1] then
+					Result := False
+				end
+				i := i + 1
+			end
 		end
-		if swapped= FALSE then
-			finished:= TRUE
-			sol:= ar
-		end
-		end
-		Result:= sol
-	end
+
 end

Task/Sorting-algorithms-Cocktail-sort/Eiffel/sorting-algorithms-cocktail-sort-2.e

@@ -1,18 +1,33 @@
 class
 	APPLICATION
-inherit
-	ARGUMENTS
+
 create
-    make
-feature
 	make
-	do
-		test:= <<5,1,99,3,2>>
-		across test as t  loop io.put_string (t.item.out + "%T")  end
-		create cs
-                test:= cs.cocktail_sort(test)
-		across test as ar loop io.put_string (ar.item.out+"%T")  end
-	end
-	cs: COCKTAIL_SORT[INTEGER]
-	test: ARRAY[INTEGER]
+
+feature
+
+	make
+		do
+			test := <<5, 1, 99, 3, 2>>
+			io.put_string ("unsorted%N")
+			across
+				test as t
+			loop
+				io.put_string (t.item.out + "%T")
+			end
+			io.new_line
+			io.put_string ("sorted%N")
+			create cs
+			test := cs.cocktail_sort (test)
+			across
+				test as ar
+			loop
+				io.put_string (ar.item.out + "%T")
+			end
+		end
+
+	cs: COCKTAIL_SORT [INTEGER]
+
+	test: ARRAY [INTEGER]
+
 end