String Replace

Question

HiBelow is my program to replace the string A to Z B to Y .. . ..... Z to A and so on PrivateSub Button1_Click(ByVal sender As System.Object ByVal e As System.EventArgs) Handles Button1.Click Dim sample As String sample = TextBox1.Text Dim letter As String = AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz Dim letter1 As String = ZzYyXxWwVvUuTtSsRrQqPpOoNnMmLlKkJjIiHhGgFfEeDdCcBbAa For Each s As String In sample Dim i As Integer For i = 0 To letter.Length - 1 If s = letter(i) Then TextBox2.Text += letter1(i) End If Next Next End Sub Here i want the program that should have only one for loop and inside the loop should not use the if conditions. Need the optimized code. Can anyone help me please

Vulpes · Answer

You can do it as long as a Select statement is permitted within the For Each statement. In fact if you do this you can cope with non-letter characters as well by simply copying them unchanged to the second textbox: Private Sub Button1_Click(ByVal sender As System.Object ByVal e As System.EventArgs) Handles Button1.Click Dim sample As String sample = TextBox1.Text TextBox2.Text =  Dim temp As String =  Dim i As Integer Dim d As Char For Each c As Char In sample Select Case c Case Ac To Zc i = AscW(c) - 64 d = ChrW(91 - i) Case ac To zc i = AscW(c) - 96 d = ChrW(123 - i) Case Else d = c End Select temp += d Next TextBox2.Text = temp End Sub

Farooque Ali · Answer

Hi Thanks for your reply But here one more thing need to be discussed The string which is declared as letter and letter1 should not use that also Is any other way there to create program without using that declaration.

Vulpes · Answer

As long as TextBox1 is guaranteed not to contain any characters other than letters then this should work. However if there are other characters you'll get an exception and the only way to prevent that is to use an 'If' statement within the For Each loop. Notice that it's best to build up the translated string within a temporary variable and then assign it to TextBox2.Text so you only have to alter the UI once: Private Sub Button1_Click(ByVal sender As System.Object ByVal e As System.EventArgs) Handles Button1.Click Dim sample As String sample = TextBox1.Text TextBox2.Text =  Dim letter As String = AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz Dim letter1 As String = ZzYyXxWwVvUuTtSsRrQqPpOoNnMmLlKkJjIiHhGgFfEeDdCcBbAa Dim temp As String =  For Each c As Char In sample Dim i As Integer = letter.IndexOf(c) temp += letter1(i) Next TextBox2.Text = temp End Sub