Question

I have a function that takes a string and returns a string. In it, I convert the string into an integer array and later try to multiply every other number like this:

private string addEveryOther(string x) 
{    
    int[] d = x.Select(n => Convert.ToInt32(n)).ToArray();

    for(int i = 0; i < 10; i++)
    {
        d[i] = d[i] * 2;
        MessageBox.Show(d[i].ToString()); //Display the result? 
        i++;
    }

    // And later returning a string:
    StringBuilder g = new StringBuilder();
    foreach (int n in d)
    {
        g.Append(Convert.ToChar(n));
    }

    return g.ToString();
}

This works with addition, but not with multiplication as it returns strange values. If I input “3434343434” i expect it to return “6464646464”. Now it returns: “f4f4f4f4f4” and I don’t know why? Any suggestions how to go about it?

Answer 1

Based on the discussions above, I suppose your method should use ToString instead of Convert.ToChar.

private string addEveryOther(string x) 
{    
  int[] d = x.Select(n => Convert.ToInt32(n.ToString())).ToArray();

  for(int i = 0; i < d.Length; i += 2)
  {
    d[i] = d[i] * 2;
    MessageBox.Show(d[i].ToString()); //Display the result? 
  }

  // And later returning a string:
  return String.Concat(d.Select(n => n.ToString()));
}

EDIT: Using @Kirill’s Concat solution and @Reniuz comment in the addEveryOther method should hopefully solve the problem.