Question

I tried to design a program which counts the vowels in a sentence.

In my code, I used a foreach statement with the if/else if statement. I would like to convert these line of code using the switch statement
but I’m not really sure where to go. Do I need to add a new method? I would appreciate your help.

This is what I tried so far: I checked this one is very wrong. The case 1 for example needs to have a constant. I’m not sure what constant shall I use here.

foreach (char v in yourSentence)
{
    switch (v)
    {
    case 1: 
        (v==ch1); 
        counta++; 
        j++; 
        break;

    case 2: 
        (v==ch2); 
        counte++; 
        j++; 
        break;
    case 3: 
        (v==ch3); 
        counti++; 
        j++; 
        break;
    case 4: 
        (v==ch4); 
        counto++; 
        j++; 
        break;
    case 5: 
        (v==ch3); 
        counti++; 
        j++; 
        break;             
    }
}

Another question: I tried to change the color of the display text in the listBox. Is that possible to have different colors? What I also tried here is the first 5 (listBox1.Items.Add) are violet. And the sum of the (listBox1.Items.Add) is blue. But it seems that it didn’t change. Did I miss something here?

private void btnCount_Click(object sender, EventArgs e)
{
    string yourSentence;
    yourSentence = textBoxVowels.Text.ToLower().Trim();

    char ch1 = 'a';
    char ch2 = 'e';
    char ch3 = 'i';
    char ch4 = 'o';
    char ch5 = 'u';

    int counta = 0;
    int counte = 0;
    int counti = 0;
    int counto = 0;
    int countu = 0;

    int j = counta + counte + counti + counto + countu;



    foreach (char v in yourSentence)
    {
        if (v == ch1) { counta++; j++; }

        else if (v == ch2) { counte++; j++; }

        else if (v == ch3) { counti++; j++; }

        else if (v == ch4) { counto++; j++; }

        else if (v == ch5) { countu++; j++; }
    }

    listBox1.Items.Add("There are " + counta.ToString().Trim() + " a's in the sentence");
    listBox1.Items.Add("There are " + counte.ToString().Trim() + " e's in the sentence");
    listBox1.Items.Add("There are " + counti.ToString().Trim() + " i's in the sentence");
    listBox1.Items.Add("There are " + counto.ToString().Trim() + " o's in the sentence");
    listBox1.Items.Add("There are " + countu.ToString().Trim() + " u's in the sentence");
    listBox1.Font = new Font("Arial", 12, FontStyle.Bold);
    listBox1.ForeColor = Color.Violet;

    listBox1.Items.Add("There are " + j.ToString().Trim() + " vowels in the sentence");
    listBox1.ForeColor = Color.Blue;
}


private void btnClear_Click(object sender, EventArgs e)
{
    textBoxVowels.Text = null;
    listBox1.Items.Clear();
}

Answer 1

I think you misunderstood how ‘switch/case’ works. Just change them to this:

case 'a': 
     counta++; 
     j++; 
     break;

Case needs a constant value that should be compared to the current character.