June 2018 Update

Task/Ethiopian-multiplication/VBA/ethiopian-multiplication-1.vba

@@ -0,0 +1,11 @@
+Private Function lngHalve(Nb As Long) As Long
+    lngHalve = Nb / 2
+End Function
+
+Private Function lngDouble(Nb As Long) As Long
+    lngDouble = Nb * 2
+End Function
+
+Private Function IsEven(Nb As Long) As Boolean
+    IsEven = (Nb Mod 2 = 0)
+End Function

Task/Ethiopian-multiplication/VBA/ethiopian-multiplication-2.vba

@@ -0,0 +1,30 @@
+Private Function Ethiopian_Multiplication_Non_Optimized(First As Long, Second As Long) As Long
+Dim Left_Hand_Column As New Collection, Right_Hand_Column As New Collection, i As Long, temp As Long
+
+'Take two numbers to be multiplied and write them down at the top of two columns.
+    Left_Hand_Column.Add First, CStr(First)
+    Right_Hand_Column.Add Second, CStr(Second)
+'In the left-hand column repeatedly halve the last number, discarding any remainders,
+    'and write the result below the last in the same column, until you write a value of 1.
+    Do
+        First = lngHalve(First)
+        Left_Hand_Column.Add First, CStr(First)
+    Loop While First > 1
+'In the right-hand column repeatedly double the last number and write the result below.
+    'stop when you add a result in the same row as where the left hand column shows 1.
+    For i = 2 To Left_Hand_Column.Count
+        Second = lngDouble(Second)
+        Right_Hand_Column.Add Second, CStr(Second)
+    Next
+
+'Examine the table produced and discard any row where the value in the left column is even.
+    For i = Left_Hand_Column.Count To 1 Step -1
+        If IsEven(Left_Hand_Column(i)) Then Right_Hand_Column.Remove CStr(Right_Hand_Column(i))
+    Next
+'Sum the values in the right-hand column that remain to produce the result of multiplying
+    'the original two numbers together
+    For i = 1 To Right_Hand_Column.Count
+        temp = temp + Right_Hand_Column(i)
+    Next
+    Ethiopian_Multiplication_Non_Optimized = temp
+End Function

Task/Ethiopian-multiplication/VBA/ethiopian-multiplication-3.vba

@@ -0,0 +1,7 @@
+Private Function Ethiopian_Multiplication(First As Long, Second As Long) As Long
+    Do
+        If Not IsEven(First) Then Mult_Eth = Mult_Eth + Second
+        First = lngHalve(First)
+        Second = lngDouble(Second)
+    Loop While First >= 1
+End Function

Task/Ethiopian-multiplication/VBA/ethiopian-multiplication-4.vba

@@ -0,0 +1,7 @@
+Sub Main_Ethiopian()
+Dim result As Long
+    result = Ethiopian_Multiplication(17, 34)
+    ' or :
+    'result = Ethiopian_Multiplication_Non_Optimized(17, 34)
+    Debug.Print result
+End Sub