vb.net - vb.net 随机数学

Question

有谁知道我将如何随机生成一个基本的数学问题，其中答案总是 1、2、3 或 4。因此，例如使用两个随机数 8 和 4，我可能会显示问题：

8 / 4 所以在这种情况下答案是 2。其他示例：2*2、8/8、4+0 等，但答案始终在 1 到 4 的范围内。谢谢

Answer 1

我在下面发布一个想法。

如果您只想使用正整数（在此示例中counterPartNumerator可能不是），则需要进行一些调整。

玩得开心！

Private _possibleNumerators() As Integer = {2, 4, 8, 12, 15, 20, 25, 32, 40} ' Random numbers I arbitrarily chose
Private _possibleResults() As Integer = {1, 2, 4, 8}
Friend Enum Operation As Integer
    Add = 0
    Subtract = 1
    Multiply = 2
    Divide = 3
End Enum

Private _randomGen As New Random

Public Sub ShowArithmeticExpression()
    Dim randomNumerator As Integer = GetRandom(_possibleNumerators)
    Dim counterPartNumerator As Decimal
    Dim randomDesiredResult As Integer = GetRandom(_possibleResults)
    Dim randomOperation As Operation = GetRandom([Enum].GetValues(GetType(Operation)))
    Dim operationSymbol As String

    ' Find counterPartNumerator
    Select Case randomOperation
        Case Operation.Add
            counterPartNumerator = randomDesiredResult - randomNumerator
            operationSymbol = "+"
        Case Operation.Subtract
            counterPartNumerator = randomNumerator - randomDesiredResult
            operationSymbol = "-"
        Case Operation.Multiply
            counterPartNumerator = randomDesiredResult / randomNumerator
            operationSymbol = "*"
        Case Operation.Divide
            counterPartNumerator = randomNumerator * randomDesiredResult
            operationSymbol = "/"
    End Select

    Console.WriteLine(String.Format("{0} {1} {2} = ?", randomNumerator, operationSymbol, counterPartNumerator))
    Console.WriteLine(String.Format("Result = {0}", randomDesiredResult))
End Sub

Private Function GetRandom(numberSet As Integer()) As Integer
    Dim minValue, maxValue As Integer

    ' Could simplify this using Linq. Eg: minValue = numberSet.Min() : maxValue = numberSet.Max()
    For Each number In numberSet
        If number < minValue Then minValue = number
        If number > maxValue Then maxValue = number
    Next

    While True
        Dim valueReturn As Integer = _randomGen.Next(minValue, maxValue)
        If numberSet.Contains(valueReturn) Then
            Return valueReturn
        End If
    End While

    Return -1
End Function

Answer 2

尝试以下代码

Dim xGenerator As System.Random = New System.Random()
        Dim xTemp As Integer = 0
        Dim c As Integer = 0
        Dim xRndNo As New List(Of Integer)

        While Not xRndNo.Count = 2

            xTemp = xGenerator.Next(0, 9)
            If c = 0 Then
                xRndNo.Add(xTemp)
            Else
                If (xRndNo.Item(0) + xTemp) Or (xRndNo.Item(0) - xTemp) Or (xRndNo.Item(0) * xTemp) Or (xRndNo.Item(0) / xTemp) <= 4 And ((xRndNo.Item(0) + xTemp) Or (xRndNo.Item(0) - xTemp) Or (xRndNo.Item(0) * xTemp) Or (xRndNo.Item(0) / xTemp)) > 0 Then
                    xRndNo.Add(xTemp)
                End If
            End If
            c = +1
        End While