Mega Code Archive
Testing the effects of passing array references using ByVal and ByRef
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Module Tester
Sub Main()
Dim i As Integer
Dim firstArray As Integer()
Dim firstArrayCopy As Integer()
firstArray = New Integer() {1, 2, 3}
firstArrayCopy = firstArray
For i = 0 To firstArray.GetUpperBound(0)
Console.Write(firstArray(i) & " ")
Next
FirstDouble(firstArray)
For i = 0 To firstArray.GetUpperBound(0)
Console.Write(firstArray(i) & " ")
Next
If firstArray Is firstArrayCopy Then
Console.WriteLine("The references are equal.")
Else
Console.WriteLine("The references are not equal.")
End If
Dim secondArray As Integer()
Dim secondArrayCopy As Integer()
secondArray = New Integer() {1, 2, 3}
secondArrayCopy = secondArray
For i = 0 To secondArray.GetUpperBound(0)
Console.Write(secondArray(i) & " ")
Next
SecondDouble(secondArray)
For i = 0 To secondArray.GetUpperBound(0)
Console.Write(secondArray(i) & " ")
Next
If secondArray Is secondArrayCopy Then
Console.WriteLine("The references are equal.")
Else
Console.WriteLine("The references are not equal.")
End If
End Sub ' Main
Sub FirstDouble(ByVal array As Integer())
Dim i As Integer
For i = 0 To array.GetUpperBound(0)
array(i) *= 2
Next
array = New Integer() {11, 12, 13}
End Sub
Sub SecondDouble(ByRef array As Integer())
Dim i As Integer
For i = 0 To array.GetUpperBound(0)
array(i) *= 2
Next
array = New Integer() {11, 12, 13}
End Sub
End Module
1 2 3 2 4 6 The references are equal.
1 2 3 11 12 13 The references are not equal.
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