I tried to chew C # (reading and writing files)

In java, it was fisfos as below ...

package fileconvert;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

public class Convert {

    public static void main(String[] args) throws IOException{
        //Read file
        FileInputStream fis=new FileInputStream("assets/sample.txt"); 
        InputStreamReader isr=new InputStreamReader(fis,"sjis");
        BufferedReader br=new BufferedReader(isr);
        //Writing a file
        FileOutputStream fos=new FileOutputStream("assets/sample2.txt");        
        OutputStreamWriter osw=new OutputStreamWriter(fos,"utf-8");
        BufferedWriter bw=new BufferedWriter(osw);

        String line;
        while((line=br.readLine())!=null) {
            bw.append(line);
            bw.newLine();
        }
        br.close();
        bw.flush();
        bw.close();
        System.out.println("done!");
        /*
        while(true) {
            String line=br.readLine();
            if(line == null) {
                break;
            }
            System.out.println(line);
        }
        */

    }

}

Use it like this in C

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace WeightApp
{
    class Program
    {
        static void Main(string[] args)
        {
            var path=@"./log.txt";
            while (true)
            {
                Console.WriteLine("Please enter the operation Please enter the operation 1...Enter your weight, 2...See list, 3...End>");
                var select = Console.ReadLine();
                switch (select)
                {
                    case "1":
                        Console.Write("Please enter your weight>");
                        var weight = double.Parse(Console.ReadLine());
                        using (var writer = new StreamWriter(path, true))

                        {
                            writer.WriteLine($"{DateTime.Now.ToString()} {weight}kg");
                        }
                        break;
                    case "2":
                        var file = new FileInfo(path);
                        //Is there or not
                        if (file.Exists)
                        {
                            using (var reader = new StreamReader(path))
                            {
                                string line;
                                while ((line = reader.ReadLine()) != null)
                                {
                                    Console.WriteLine(line);
                                }
                            }

                        }
                        else
                        {
                            Console.WriteLine("There is no data yet.");
                        }
                        break;
                    default:
                        Console.WriteLine("Exit the app.");
                        return;
                }
            }
        }
    }
}

It is recognition. I'm not proud, but only fisfos can understand the mechanism and memorize it.

It's a mystery myself. ..