Do Loop Until and Do While Loop in VB Exercise and Example Question

Do Loop Until  and Do While Loop in Visual Basic Exercise and Example Practice Question 

Do While Loop

A loop is one of the most important structures in VB and is used to repeat a sequence of statements a number of times.

The Do While Loop repeats a sequence of statements either as long as or until a certain condition is true.

Do While condition

            statements

Loop

Exercise

1.         Sub Command1_Click ( )

Dim num As Integer

Let num=1

Do While num<=10

            Picture1.Print num;

            Let num=num+1

Loop

End Sub 

2          Sub Command1_Click ( )

Dim passWord as String, info As String

If Ucase(Text1.Text) = “SECRET.TXT” Then

                        Let passWord=“”

            Do While passWord <> “SHAHID”

                        Let passWord = InputBox$(“Enter passWord”)

                        Let passWord = Ucase(passWord)

            Loop

            End If

            Open Text1.Text For Input As #1

Input #1, info

Picture1.Print info

Close #1

End Sub

.

Do Loop Until

A loop is one of the most important structures in VB and is used to repeat a sequence of statements a number of times.

The Do Loop Until executes the statement(s) once and then  repeats a sequence of statements either as long as or until a certain condition is true.

Do

.

            .

            statements

            .

            .

Loop Until condition

A Do Loop of this form executes the statements inside the loop (at least once) and then checks the truth value of the condition. If the condition is true then the program continues with the line after the Loop statement. But if the condition is false then the entire process is repeated beginning with the Do statement.

Exercise –

Private Sub Command1_Click()

    Dim pw As String, info As String

    Do

        pw = InputBox$("What is the password?")

        pw = UCase$(pw)

    Loop Until pw = "NATASHA"

   

    Open "Secret.txt" For Input As #1

    Input #1, info

    Picture1.Print info

    Close #1

End Sub