using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;

namespace Sizedown
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            int N = 0;
            if (openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                label1.Text = openFileDialog1.FileName;
                String OutText = "";

                StreamReader sr = new StreamReader(openFileDialog1.FileName, Encoding.GetEncoding("Shift_JIS"));
                try
                {
                    while (sr.EndOfStream == false)
                    {
                        string line = sr.ReadLine();

                        if((N- Convert.ToInt32(textBox3.Text)) % Convert.ToInt32(textBox2.Text) == 0)
                        {
                            OutText += line + "\r\n";
                        }
                        N++;
                    }
                }
                finally
                {
                    textBox1.Text = N.ToString()+"行でした！！\r\n";
                    sr.Close();
                    if (saveFileDialog1.ShowDialog() == DialogResult.OK)
                    {
                        using (StreamWriter outfile = new StreamWriter(saveFileDialog1.FileName))
                        {
                            outfile.Write(OutText);
                        }
                    }
                }
            }

        }
    }
}