Initial data commit

Task/Greatest-common-divisor/Visual-Basic/greatest-common-divisor.vb

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+Function GCD(ByVal a As Long, ByVal b As Long) As Long
+Dim h As Long
+
+    If a Then
+        If b Then
+            Do
+                h = a Mod b
+                a = b
+                b = h
+            Loop While b
+        End If
+        GCD = Abs(a)
+    Else
+        GCD = Abs(b)
+    End If
+
+End Function
+
+Sub Main()
+' testing the above function
+
+  Debug.Assert GCD(12, 18) = 6
+  Debug.Assert GCD(1280, 240) = 80
+  Debug.Assert GCD(240, 1280) = 80
+  Debug.Assert GCD(-240, 1280) = 80
+  Debug.Assert GCD(240, -1280) = 80
+  Debug.Assert GCD(0, 0) = 0
+  Debug.Assert GCD(0, 1) = 1
+  Debug.Assert GCD(1, 0) = 1
+  Debug.Assert GCD(3475689, 23566319) = 7
+  Debug.Assert GCD(123456789, 234736437) = 3
+  Debug.Assert GCD(3780, 3528) = 252
+
+End Sub