Question

尝试使用visual basic为学校项目制作一个随机数生成器。用户将在textbox1和textbox 2中输入2个不同的值，按下按钮，这两个数字之间将生成一个随机数（此随机数将显示在textbox3中）。这对于项目来说太基础了，所以我决定添加2个复选框，当选中时会使生成的数字变为偶数或奇数。

真的需要一些算法来帮助将随机数限制为偶数或奇数。任何帮助是极大的赞赏！ :)（checkbox1用于使其均匀，checkbox2用于奇数）

Dim answer As Integer
Dim result As Integer




Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

    TextBox3.Clear()
    TextBox3.Text = answer

    If CheckBox1.Checked = False And CheckBox2.Checked = False Then
        answer = CInt(Int((TextBox2.Text * Rnd() + TextBox1.Text)))
    End If

^上面的代码似乎也按照特定的顺序生成随机数，总是从0开始，对此的任何帮助将不胜感激：）

    If CheckBox1.Checked = True Then
        Do Until result = 0
            result = CDec(TextBox1.Text / 2) - CInt(TextBox1.Text / 2)

        Loop
        If result = 0 Then
            answer = CInt(Int((TextBox2.Text * Rnd() + TextBox1.Text)))
        End If



    End If

End Sub

Answer 1

这就是我要解决这个问题的方法：

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) 'Handles Button1.Click

    'Parse the two numbers
    Dim minValue = Integer.Parse(TextBox1.Text)
    Dim maxValue = Integer.Parse(TextBox2.Text)

    'Create a list of all possible valid numbers
    Dim values = Enumerable.Range(minValue, maxValue - minValue).ToArray()

    'Keep only the even numbers if selected
    If CheckBox1.Checked Then
        values = values.Where(Function (v) v Mod 2 = 0).ToArray()
    End If

    'Keep only the odd numbers if selected
    If CheckBox2.Checked Then
        values = values.Where(Function (v) v Mod 2 = 1).ToArray()
    End If

    'Check there are numbers
    If values.Length = 0 Then
        TextBox3.Text = "There no available numbers to choose."
    Else
        '`rnd` here is `System.Random` as I didn't know what `Rnd()` was.
        TextBox3.Text = values(rnd.Next(0, values.Length)).ToString()
    End If

End Sub

Answer 2

您可以使用函数生成偶数或奇数，具体取决于选中的复选框，函数将使用mod来确定生成的数字是偶数/奇数。如果它不是您所需要的，那么它将再次尝试，直到生成的数字匹配。例如：

  Private Sub btnGenerate_Click(sender As System.Object, e As System.EventArgs) Handles btnGenerate.Click
    If chkOdd.Checked Then
        GenerateOdd()
    ElseIf chkEven.Checked Then
        GenerateEven()
    End If
End Sub

Private Function GenerateOdd()
    Dim r = CInt(Math.Ceiling(Rnd() * 100))
    If ((r Mod 2) = 0) Then
        'r is even, generate another number and try again
        GenerateOdd()
    Else
        'r is odd we have a match
        yourTextBox.Text = r
        Return r
    End If
    Return Nothing
End Function

Private Function GenerateEven()
    Dim r = CInt(Math.Ceiling(Rnd() * 100))
    If ((r Mod 2) = 0) Then
        'r is even, we have a match
        yourTextBox.Text = r
        Return r
    Else
        'r is odd, generate another number and try again
        GenerateEven()
    End If
    Return Nothing
End Function

我还没有尝试过，但你明白了！

*编辑 - （Rnd（）* 100））是1到100之间的随机数

在visual basic中使用随机数生成器专门获得偶数/奇数

2 个答案: