CODEWITHSUNDEEP
vb.netstringsubstring
CodingIsHardForMe
CodingIsHardForMe

Reputation: 93

Count specific character in string using SubString

I'm teaching myself VB.net and I'm trying to complete challenges.

I'm stuck on this challenge.

I'm trying to figure out how to go about counting specific characters in a string using SubString.

I should not use string processing functions other than: Trim, ToUpper, ToLower, Indexof, SubString.

Add one button for each vowel of the alphabet. When clicked, the output is the count of that vowel in the text entered.Using SubString, the code under the button click event handler,displays how many times the corresponding character appears in the text.

This is what I have so far, but how should I incorporate SubString?

    Dim counter As Integer = 0
    For Each vowelA As Char In TextBox1.Text
        If vowelA = "a" Then
            counter += 1
        End If

        If vowelA = "A" Then
            counter += 1
        End If

    Next

Upvotes: 0

Views: 612

Answers (3)

Vivek S.
Vivek S.

Reputation: 21885

Without using a substring() function,

 Function count_vowels(ByVal str As String, ByVal chr As String) As Integer
        str = str.ToUpper()
        chr = chr.ToUpper()
        count_vowels = str.Split(chr).Length - 1
        Return count_vowels
 End Function

Usage:

Dim counter As Integer = 0
counter = count_vowels(TextBox3.Text, "a")

or simply use

 counter = TextBox1.Text.ToUpper.Split("a".ToUpper).Length - 1

Upvotes: 1

Aethan
Aethan

Reputation: 1985

Here I incorporated also .ToUpper so you don't need to compare "a" and "A"

Dim counter As Integer = 0
For i = 0 To TextBox1.Text.Length - 1
    If TextBox1.Text.ToUpper.Substring(i, 1) = "A" Then
        counter += 1
    End If
Next

Upvotes: 2

Serge
Serge

Reputation: 4036

Try something like this:

    Dim pos As Integer = 0
    Dim letter as String
    While pos < TextBox1.Text.Length
        letter = TextBox1.Text.Substring(pos, 1)
        If letter = "A" Then
            counter += 1
        End If

        pos += 1
    End While

Upvotes: 0

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