Another update from ingydotnet^djgoku

Task/Sorting-algorithms-Merge-sort/Eiffel/sorting-algorithms-merge-sort-1.e

@@ -1,60 +1,68 @@
 class
 	MERGE_SORT [G -> COMPARABLE]
+
 create
 	sort
+
 feature
-	sort(ar: ARRAY[G])
-	-- sort array ar with mergesort and save it in sorted_array
-           require
-           	ar_not_empty: ar.is_empty= FALSE
-           do
+
+	sort (ar: ARRAY [G])
+			-- Sorted array in ascending order.
+		require
+			ar_not_empty: not ar.is_empty
+		do
 			create sorted_array.make_empty
-			mergesort(ar, 1, ar.count)
-			sorted_array:= ar
-		   ensure
-		   	sorted_array_not_empty: sorted_array.is_empty = FALSE
-		   	sorted: is_sorted(sorted_array, 1, sorted_array.count)= TRUE
-	       end
-	sorted_array: ARRAY[G]
+			mergesort (ar, 1, ar.count)
+			sorted_array := ar
+		ensure
+			sorted_array_not_empty: not sorted_array.is_empty
+			sorted: is_sorted (sorted_array, 1, sorted_array.count)
+		end
+
+	sorted_array: ARRAY [G]
+
 feature {NONE}
-	mergesort(ar:ARRAY[G]; l,r:INTEGER)
+
+	mergesort (ar: ARRAY [G]; l, r: INTEGER)
+			-- Sorting part of mergesort.
 		local
 			m: INTEGER
 		do
-			if l<r then
-				m := (l+r)//2
-				mergesort(ar,l, m)
-				mergesort(ar,m+1,r)
-				merge(ar,l,m,r)
+			if l < r then
+				m := (l + r) // 2
+				mergesort (ar, l, m)
+				mergesort (ar, m + 1, r)
+				merge (ar, l, m, r)
 			end
 		end
 
-	merge(ar:ARRAY[G]; l,m,r: INTEGER)
+	merge (ar: ARRAY [G]; l, m, r: INTEGER)
+			-- Merge part of mergesort.
 		require
-			positive_index_l: l>=1
-			positive_index_m: m>=1
-			positive_index_r: r>=1
-			ar_not_empty: ar.is_empty= FALSE
+			positive_index_l: l >= 1
+			positive_index_m: m >= 1
+			positive_index_r: r >= 1
+			ar_not_empty: not ar.is_empty
 		local
-			merged: ARRAY[G]
-			h,i,j,k: INTEGER
+			merged: ARRAY [G]
+			h, i, j, k: INTEGER
 		do
 			i := l
-			j := m+1
+			j := m + 1
 			k := l
-			create merged.make_empty
+			create merged.make_filled (ar [1], 1, ar.count)
 			from
 			until
 				i > m or j > r
 			loop
 				if ar.item (i) <= ar.item (j) then
-					merged.force(ar.item(i),k)
-					i := i +1
+					merged.force (ar.item (i), k)
+					i := i + 1
 				elseif ar.item (i) > ar.item (j) then
-					merged.force(ar.item(j),k)
-					j := j+1
+					merged.force (ar.item (j), k)
+					j := j + 1
 				end
-				k := k+1
+				k := k + 1
 			end
 			if i > m then
 				from
@@ -62,8 +70,8 @@ feature {NONE}
 				until
 					h > r
 				loop
-					merged.force(ar.item(h),k+h-j)
-					h := h+1
+					merged.force (ar.item (h), k + h - j)
+					h := h + 1
 				end
 			elseif j > m then
 				from
@@ -71,8 +79,8 @@ feature {NONE}
 				until
 					h > m
 				loop
-					merged.force(ar.item(h),k+h-i)
-					h := h+1
+					merged.force (ar.item (h), k + h - i)
+					h := h + 1
 				end
 			end
 			from
@@ -81,37 +89,32 @@ feature {NONE}
 				h > r
 			loop
 				ar.item (h) := merged.item (h)
-				h := h+1
+				h := h + 1
 			end
-			ensure
-				is_partially_sorted: is_sorted(ar, l,r)= TRUE
+		ensure
+			is_partially_sorted: is_sorted (ar, l, r)
 		end
 
-	is_sorted(ar: ARRAY[G];l, r: INTEGER): BOOLEAN
-                --- feature is not required for mergesort but is used for contracts
+	is_sorted (ar: ARRAY [G]; l, r: INTEGER): BOOLEAN
+			-- Is 'ar' sorted in ascending order?
 		require
-			ar_not_empty: ar.is_empty= FALSE
+			ar_not_empty: not ar.is_empty
 			l_in_range: l >= 1
 			r_in_range: r <= ar.count
 		local
-			smaller : BOOLEAN
 			i: INTEGER
 		do
-			smaller:= TRUE
+			Result := True
 			from
-				i:= l
+				i := l
 			until
-				i=r
+				i = r
 			loop
-				if ar[i]> ar[i+1]	then
-					smaller:= FALSE
+				if ar [i] > ar [i + 1] then
+					Result := False
 				end
-				i:= i+1
-			end
-			if smaller = TRUE then
-				RESULT := TRUE
-			else
-				RESULT:= FALSE
+				i := i + 1
 			end
 		end
+
 end

Task/Sorting-algorithms-Merge-sort/Eiffel/sorting-algorithms-merge-sort-2.e

@@ -1,19 +1,31 @@
 class
 	APPLICATION
-inherit
-	ARGUMENTS
+
 create
-    make
-feature
 	make
-	do
-		test:= <<2,5,66,-2, 0, 7>>
-		io.put_string ("unsorted"+ "%N")
-		across test as ar loop io.put_string (ar.item.out + "%T")  end
-		io.put_string ("%N"+"sorted"+ "%N")
-		create merge.sort (test)
-		across merge.sorted_array as ar loop io.put_string (ar.item.out + "%T")  end
-	end
-	test: ARRAY[INTEGER]
-	merge: MERGE_SORT[INTEGER]
+
+feature
+
+	make
+		do
+			test := <<2, 5, 66, -2, 0, 7>>
+			io.put_string ("unsorted" + "%N")
+			across
+				test as ar
+			loop
+				io.put_string (ar.item.out + "%T")
+			end
+			io.put_string ("%N" + "sorted" + "%N")
+			create merge.sort (test)
+			across
+				merge.sorted_array as ar
+			loop
+				io.put_string (ar.item.out + "%T")
+			end
+		end
+
+	test: ARRAY [INTEGER]
+
+	merge: MERGE_SORT [INTEGER]
+
 end