Data commit

Task/Stack/VBA/stack-1.vba

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+'Simple Stack class
+
+'uses a dynamic array of Variants to stack the values
+'has read-only property "Size"
+'and methods "Push", "Pop", "IsEmpty"
+
+Private myStack()
+Private myStackHeight As Integer
+
+'method Push
+Public Function Push(aValue)
+  'increase stack height
+  myStackHeight = myStackHeight + 1
+  ReDim Preserve myStack(myStackHeight)
+  myStack(myStackHeight) = aValue
+End Function
+
+'method Pop
+Public Function Pop()
+  'check for nonempty stack
+  If myStackHeight > 0 Then
+    Pop = myStack(myStackHeight)
+    myStackHeight = myStackHeight - 1
+  Else
+    MsgBox "Pop: stack is empty!"
+  End If
+End Function
+
+'method IsEmpty
+Public Function IsEmpty() As Boolean
+  IsEmpty = (myStackHeight = 0)
+End Function
+
+'property Size
+Property Get Size() As Integer
+  Size = myStackHeight
+End Property

Task/Stack/VBA/stack-2.vba

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+'stack test
+Public Sub stacktest()
+  Dim aStack As New Stack
+  With aStack
+    'push and pop some value
+    .Push 45
+    .Push 123.45
+    .Pop
+    .Push "a string"
+    .Push "another string"
+    .Pop
+    .Push Cos(0.75)
+    Debug.Print "stack size is "; .Size
+    While Not .IsEmpty
+      Debug.Print "pop: "; .Pop
+    Wend
+    Debug.Print "stack size is "; .Size
+    'try to continue popping
+    .Pop
+  End With
+End Sub