Question

I need to take a sentence in that is all on one line with no spaces and each new word has a captial letter EX. “StopAndSmellTheRoses” and then convert it to “Stop and smell the roses” This is my function that I have but I keep getting an argument out of range error on the insert method. Thanks for any help in advance.

private void FixSentence()
{
    // String to hold our sentence in trim at same time
    string sentence = txtSentence.Text.Trim();

    // loop through the string
    for (int i = 0; i < sentence.Length; i++)
    {
        if (char.IsUpper(sentence, i) & sentence[i] != 0)
        {
            // Change to lowercase
            char.ToLower(sentence[i]);

            // Insert space behind the character
            // This is where I get my error
            sentence = sentence.Insert(i-1, " ");
        }
    }

    // Show our Fixed Sentence
    lblFixed.Text = "";
    lblFixed.Text = "Fixed: " + sentence;
}

Answer 1

The best way to build up a String in this manner is to use a StringBuilder instance.

var sentence = txtSentence.Text.Trim();
var builder = new StringBuilder();
foreach (var cur in sentence) {
  if (Char.IsUpper(cur) && builder.Length != 0) {
    builder.Append(' ');
  }
  builder.Append(cur);
}

// Show our Fixed Sentence
lblFixed.Text = "";
lblFixed.Text = "Fixed: " + builder.ToString();

Using the Insert method creates a new string instance every time resulting in a lot of needlessly allocated values. The StringBuilder though won’t actually allocate a String until you call the ToString method.