vb练习题及答案
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vb练习题及答案
VB练习题及答案
VB(Visual Basic)是一种广泛应用于Windows操作系统的编程语言,它以其简单易学的特点受到了许多初学者和专业开发者的青睐。为了帮助大家更好地掌握VB编程,下面将提供一些VB练习题及其答案,希望能对大家有所帮助。
练习题一:计算器程序
编写一个VB程序,实现一个简单的计算器功能。要求用户输入两个数字和一个操作符(+、-、*、/),然后根据操作符进行相应的计算,并输出结果。
解答:
```vb
Private Sub btnCalculate_Click(sender As Object, e As EventArgs) Handles btnCalculate.Click
Dim num1 As Double = CDbl(txtNum1.Text)
Dim num2 As Double = CDbl(txtNum2.Text)
Dim operator As String = cmbOperator.SelectedItem.ToString()
Dim result As Double
Select Case operator
Case "+"
result = num1 + num2
Case "-"
result = num1 - num2
Case "*"
result = num1 * num2
Case "/"
result = num1 / num2
End Select
lblResult.Text = "Result: " & result.ToString()
End Sub
```
练习题二:学生成绩管理系统
编写一个VB程序,实现一个简单的学生成绩管理系统。要求用户输入学生的姓名和成绩,然后将其保存到数组中。用户可以通过输入姓名来查询学生的成绩。
解答:
```vb
Private Structure Student
Public Name As String
Public Score As Double
End Structure
Private students() As Student
Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click
Dim newStudent As Student
= txtName.Text
newStudent.Score = CDbl(txtScore.Text)
ReDim Preserve students(students.Length)
students(students.Length - 1) = newStudent
txtName.Text = ""
txtScore.Text = ""
End Sub
Private Sub btnSearch_Click(sender As Object, e As EventArgs) Handles btnSearch.Click
Dim searchName As String = txtSearchName.Text
Dim found As Boolean = False
For Each student As Student In students
If = searchName Then
lblSearchResult.Text = "Score: " & student.Score.ToString()
found = True
Exit For
End If
Next
If Not found Then
lblSearchResult.Text = "Student not found."
End If
End Sub
```
练习题三:简单的文本编辑器
编写一个VB程序,实现一个简单的文本编辑器功能。用户可以打开一个文本文件,编辑其中的内容,并保存修改后的文件。
解答:
```vb
Private Sub btnOpen_Click(sender As Object, e As EventArgs) Handles btnOpen.Click
Dim openFileDialog As New OpenFileDialog()
openFileDialog.Filter = "Text Files (*.txt)|*.txt"
If openFileDialog.ShowDialog() = DialogResult.OK Then
Dim fileContent As String =
puter.FileSystem.ReadAllText(openFileDialog.FileName)
txtEditor.Text = fileContent
End If
End Sub
Private Sub btnSave_Click(sender As Object, e As EventArgs) Handles btnSave.Click
Dim saveFileDialog As New SaveFileDialog()
saveFileDialog.Filter = "Text Files (*.txt)|*.txt"
If saveFileDialog.ShowDialog() = DialogResult.OK Then
puter.FileSystem.WriteAllText(saveFileDialog.FileName, txtEditor.Text, False)