CODEWITHSUNDEEP
vb.net
0000
0000

Reputation: 677

displaying a word backwards vb

i've been trying to figure this out for the last hour, i almost got it to work, but it just displays the word un-reversed. I don't know why this is. I know its a beginner question but please help. Thanks.

Private Sub btnReverse_Click(sender As Object, e As EventArgs) Handles btnReverse.Click

    Dim strInput As String
    Dim strLetter As String
    Dim intLength As Integer

    strInput = txtWord.Text
    intLength = strInput.Length
    '!!de-incremented because index starts at 0!!
    intLength = intLength - 1

    Dim indexReverse As Integer = intLength

    For index As Integer = 0 To intLength Step +1
        'get letter at this index
        strLetter = strInput.Substring(index, 1)
        'remove letter just got
        strInput = strInput.Remove(index, 1)
        'insert new letter at old letter place
        strInput = strInput.Insert(indexReverse, strLetter)

        indexReverse = indexReverse - 1
    Next

    lblReverse.Text = strInput

End Sub

Ok so i edited my code as per kjtl's idea, now im getting an argumentoutofrange exeption. I know what that means but i dont understand why im getting that exeption. To reiterate, i want to Edit this code as little as possible to get it to work. Both ideas were easier ways of doing this, i just want to fix my code without replacing it all for educational purposes.

Private Sub btnReverse_Click(sender As Object, e As EventArgs) Handles btnReverse.Click

    Dim strInput As String
    Dim strOutput As String = ""
    Dim strLetter As String
    Dim intLength As Integer
    Dim chrPadding As Char = Convert.ToChar(" ")

    strInput = txtWord.Text
    intLength = strInput.Length
    '!!de-incremented because index starts at 0!!
    intLength = intLength - 1

    Dim indexReverse As Integer = intLength

    For index As Integer = 0 To intLength Step +1
        'get letter at this index
        strLetter = strInput.Substring(index, 1)
        'assign temp values to strOutput
        strOutput = strOutput.PadRight(intLength, chrPadding)
        'remove letter just got
        strOutput = strOutput.Remove(index, 1)
        'insert new letter at old letter place
        strOutput = strOutput.Insert(indexReverse, strLetter)

        indexReverse = indexReverse - 1
    Next

    lblReverse.Text = strInput

End Sub

Upvotes: 1

Views: 1425

Answers (2)

Steve
Steve

Reputation: 216293

The Array class has a Reverse method that

Reverses the sequence of the elements in the entire one-dimensional Array

Now, the string class has a method that extract the single char elements of the string as an array of chars. At this point the solution is really simple.

Dim strInput = "This is a Test"
Dim c = test.ToCharArray()
Array.Reverse(c)
Dim reversed = new String(c)
Console.WriteLine(reversed)

Or if you like a one liner solution

Dim strInput = "This is a Test"
Dim reversed = new String(strInput.ToCharArray().Reverse().ToArray())

Upvotes: 4

Victor Zakharov
Victor Zakharov

Reputation: 26424

You can use StrReverse:

Dim str As String = "hello"
Dim strRev As String = StrReverse(str) 'olleh

Or this (if you prefer to avoid using VisualBasic namespace):

Dim strRev2 As New String(str.Reverse.ToArray) 'olleh

See also:

Upvotes: 3

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