实验8-6

VB程序题：编写一个随机文件程序。
要求：
（1）建立一个具有5个学生的学号、姓名和成绩的随机文件(Random. dat)。
（2）读出Random．dat文件中的内容，然后按成绩排序，最后按顺序写入另一个随机文件(Randoml．dat)。
（3）再一次读出文件的内容，按文件中的顺序将学生的信息显示在屏幕上，检查正确性。

解题，画3个按钮控件，代码如下：

Private Type Studtype
    no As String * 4
    name As String * 6
    mark As Single
End Type
Dim Student As Studtype, Stud(1 To 5) As Studtype, t As Studtype

Private Sub Command1_Click()
    Open "C:\Random.dat" For Random As #1 Len = Len(Student)
    With Student
        .no = "0001"
        .name = "张三"
        .mark = 66
    End With
    Put #1, 1, Student

    With Student
        .no = "0002"
        .name = "李四"
        .mark = 99
    End With
    Put #1, 2, Student

    With Student
        .no = "0003"
        .name = "王五"
        .mark = 88
    End With
    Put #1, 3, Student

    With Student
        .no = "0004"
        .name = "赵六"
        .mark = 55
    End With
    Put #1, 4, Student

    With Student
        .no = "0005"
        .name = "钱七"
        .mark = 77
    End With
    Put #1, 5, Student

    Close #1
End Sub

Private Sub Command2_Click()

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    Open "C:\Random.dat" For Random As #1 Len = Len(Student) 
Print
Print "Random.dat 文件内容："
    For i = 1 To 5
        Get #1, i, Student
        Print Student.no, Student.name, Student.mark
        Stud(i) = Student
    Next i
    Close #1

    For i = 1 To 5
        For j = i + 1 To 5
            If Stud(i).mark > Stud(j).mark Then t = Stud(i): Stud(i) = Stud(j): Stud(j) = t '按成绩排序
        Next j
    Next i

    Open "C:\Random1.dat" For Random As #2 Len = Len(Student)

    For i = 1 To 5
        Put #2, i, Stud(i)
    Next i

    Close #1
End Sub

Private Sub Command3_Click()
    Open "C:\Random1.dat" For Random As #1 Len = Len(Student)

Print
Print "Random1.dat 文件内容："
    For i = 1 To 5
        Get #1, i, Student
        Print Student.no, Student.name, Student.mark
        Stud(i) = Student
    Next i
    Close #1
End Sub