langs a-z

Task/Balanced-brackets/VBA/balanced-brackets.vba

@@ -0,0 +1,66 @@
+Public Function checkBrackets(s As String) As Boolean
+'function checks strings for balanced brackets
+Dim Depth As Integer
+Dim ch As String * 1
+
+Depth = 0
+For i = 1 To Len(s)
+  ch = Mid$(s, i, 1)
+  If ch = "[" Then Depth = Depth + 1
+  If ch = "]" Then
+    If Depth = 0 Then 'not balanced
+      checkBrackets = False
+      Exit Function
+    Else
+      Depth = Depth - 1
+    End If
+  End If
+Next
+checkBrackets = (Depth = 0)
+End Function
+
+Public Function GenerateBrackets(N As Integer) As String
+'generate a string with N opening and N closing brackets in random order
+Dim s As String
+Dim N2 As Integer, j As Integer
+Dim Brackets() As String * 1
+Dim temp As String * 1
+
+'catch trivial value
+If N <= 0 Then
+  GenerateBrackets = ""
+  Exit Function
+End If
+
+N2 = N + N
+ReDim Brackets(1 To N2)
+For i = 1 To N2 Step 2
+ Brackets(i) = "["
+ Brackets(i + 1) = "]"
+Next i
+'shuffle.
+For i = 1 To N2
+  j = 1 + Int(Rnd() * N2)
+  'swap brackets i and j
+  temp = Brackets(i)
+  Brackets(i) = Brackets(j)
+  Brackets(j) = temp
+Next i
+'generate string
+s = ""
+For i = 1 To N2
+  s = s & Brackets(i)
+Next i
+GenerateBrackets = s
+End Function
+
+Public Sub BracketsTest()
+Dim s As String
+Dim i As Integer
+
+For i = 0 To 10
+ s = GenerateBrackets(i)
+ Debug.Print """" & s & """: ";
+ If checkBrackets(s) Then Debug.Print " OK" Else Debug.Print " Not OK"
+Next
+End Sub