Question

我正在尝试在Visual Basic 2012中创建一个应用程序，我很难让它满足参数。我究竟做错了什么？每当我尝试添加Else时，它都说必须有一个If在它之前。问题：

为大学招生办公室写一个程序。创建存储数字高中成绩点平均值和入学考试成绩的变量（例如，如果gpa> = 3.6且得分> = 60，则可以使用“和”两个不同的标准）打印消息“接受”如果学生有以下任何一项：

平均成绩为3.6或以上，入学考试成绩至少为60
平均成绩为3.0或以上，入学考试成绩至少为70
平均成绩为2.6或以上，入学考试成绩至少为80
平均成绩2.0或以上，入学考试成绩至少为90％

如果学生不符合任何资格，请打印“拒绝”。下面的图片将为您提供界面外观的参考。

    If txtGPA.Text >= 3.6 And txtAdmissionTestScore.Text >= 60 Then txtAdmissionResult.Text = "Accept"
    If txtGPA.Text >= 3.6 And txtAdmissionTestScore.Text <= 59 Then txtAdmissionResult.Text = "Reject"

    If txtGPA.Text >= 3.0 And txtAdmissionTestScore.Text >= 70 Then txtAdmissionResult.Text = "Accept"
    If txtGPA.Text >= 3.0 And txtAdmissionTestScore.Text <= 69 Then txtAdmissionResult.Text = "Reject"

    If txtGPA.Text >= 2.6 And txtAdmissionTestScore.Text >= 80 Then txtAdmissionResult.Text = "Accept"
    If txtGPA.Text >= 2.6 And txtAdmissionTestScore.Text <= 79 Then txtAdmissionResult.Text = "Reject"

    If txtGPA.Text >= 2.0 And txtAdmissionTestScore.Text >= 90 Then txtAdmissionResult.Text = "Accept"
    If txtGPA.Text >= 2.0 And txtAdmissionTestScore.Text <= 89 Then txtAdmissionResult.Text = "Reject"

    If txtGPA.Text <= 1.9 And txtAdmissionTestScore.Text <= 59 Then txtAdmissionResult.Text = "Reject"

Answer 1

你需要做这样的事情。注意我正在检查常见条件，然后检查子条件，子条件是接受或拒绝。因此，您只需要测试一个。

If txtGPA.Text >= 3.6 Then 
    If txtAdmissionTestScore.Text >= 60 Then 
        txtAdmissionResult.Text = "Accept"
    Else
        txtAdmissionResult.Text = "Reject"
    End If
ElseIf txtGPA.Text >= 3.0 Then   
    If txtAdmissionTestScore.Text >= 70 Then 
         txtAdmissionResult.Text = "Accept"
     Else
         txtAdmissionResult.Text = "Reject"
     Endif
ElseIf ...

End If

Answer 2

这只是道格拉斯·巴宾的代码重新格式化的可读性（这显然是非常主观的！），，最后一个条件被移除，因为你不能以低于2.0的GPA录取。我还添加了支票以确保输入的GPA和测试分数分别是有效的双倍和整数：

    Dim GPA As Double
    Dim AdmissionTestScore As Integer
    If Double.TryParse(txtGPA.Text, GPA) AndAlso Integer.TryParse(txtAdmissionTestScore.Text, AdmissionTestScore) Then
        Dim shouldAccept As Boolean = _
            (GPA >= 3.6 AndAlso AdmissionTestScore >= 60) OrElse _
            (GPA >= 3.0 AndAlso AdmissionTestScore >= 70) OrElse _
            (GPA >= 2.6 AndAlso AdmissionTestScore >= 80) OrElse _
            (GPA >= 2.0 AndAlso AdmissionTestScore >= 90)
        txtAdmissionResult.Text = If(shouldAccept, "Accept", "Reject")
    Else
        MessageBox.Show("Invalid GPA and/or Admission Test Score!")
    End If

Answer 3

Dim shouldAccept As Boolean = (txtGPA.Text >= 3.6 AndAlso txtAdmissionTestScore.Text >= 60) OrElse _ 
    (txtGPA.Text >= 3.0 AndAlso txtAdmissionTestScore.Text >= 70) OrElse _
    (txtGPA.Text >= 2.6 AndAlso txtAdmissionTestScore.Text >= 80) OrElse _
    (txtGPA.Text >= 2.0 AndAlso txtAdmissionTestScore.Text >= 90)

txtAdmissionResult.Text = If(shouldAccept, "Accept", "Reject")

如果......那么...... Else Visual Basic 2012

3 个答案: