Logical error in writing data in a text file in one column

Question

My Usecase is to read data from a textfile by browsing to the location of the file containing the data to be quoted.the data from the file is save in a list. i use arraylist to get the data and loop through the arraylist and concatenate each string then create output file to store the data in single column as demostrated below

Example of a string:    
20050000    
40223120    
40006523

sample out put:

'20050000',    
'40223120',    
'40006523'    
But my code is currently displaying the output in the format:
'20050000'20050000,
'40223120'20050000,
'40006523'40006523    

Pls help.

public List<string> list()
    {
        List<string> Get_Receiptlist = new List<string>();
        String ReceiptNo;
        openFileDialog1.ShowDialog();
        string name_of_Textfile = openFileDialog1.FileName;
        try
        {
            StreamReader sr = new StreamReader(name_of_Textfile);
            {
                while ((ReceiptNo = sr.ReadLine()) != null)
                {
                    Get_Receiptlist.Add(ReceiptNo);
                } // end while
                MessageBox.Show("Record saved in the Data list");// just for testing purpose.
            }// end StreamReader

        }
        catch (Exception err)
        {
            MessageBox.Show("Cannot read data from file");
        }
        return Get_Receiptlist;
    }
    private void button2_Click(object sender, EventArgs e)
    {
        string single_quotation = "'";
        string comma = ",";
        string paths = @"C:\Users\sample\Desktop\FileStream\Output.txt";
        if (!File.Exists(paths))
        {
            // Create a file to write to. 
            using (StreamWriter sw = File.CreateText(paths))
            {
                string[] receipt = list().ToArray();
                foreach (string rec in receipt)
                {
                    string quoted_receipt = single_quotation + rec + single_quotation + rec + comma;
                    sw.WriteLine(quoted_receipt);
                    sw.WriteLine(Environment.NewLine);
                }//foreach

                sw.Close();

                MessageBox.Show("Finish processing File");
            }//end using
        }// end if
    }

Answer 1

In your method button2_Click you have bad loop:

string[] receipt = list().ToArray();
foreach (string rec in receipt)
{
  string quoted_receipt = single_quotation + rec + single_quotation + rec + comma;
  sw.WriteLine(quoted_receipt);
  sw.WriteLine(Environment.NewLine);
}//foreach

First I'm not even sure its Java ... but if it was Java, then I would replace this fragment with this:

List<String> values = list();
for (int i = 0; i < values.size(); i++)
{
  String rec = values.get(i);
  StringBuilder quoted_receipt = new StringBuilder();
  if (i > 0) 
  {
    // add comma only if the first iteration already passed
    quoted_receipt.append(comma);
  }
  quoted_receipt.append(single_quotation).append(rec).append(single_quotation);
  sw.WriteLine(quoted_receipt.toString());
  sw.WriteLine(Environment.NewLine);
}