reader_writer.cs

using System;
using System.Threading;


class Program 
{
    static int data = 0;
    static ReaderWriterLock rwlock = new ReaderWriterLock();
    
    static void Main(string[] args)
    {
        new Thread(Read).Start();
        new Thread(Read).Start();
        new Thread(Write).Start('A');
        new Thread(Write).Start('B');
    }

    static void Read()
    {
        rwlock.AcquireReaderLock(Timeout.Infinite);
        try
        {
            Console.WriteLine($"Reading data: {data}");
        } finally 
        {
            rwlock.ReleaseReaderLock();
        }
    }

    static void Write(object threadID)
    {
        rwlock.AcquireWriterLock(Timeout.Infinite);
        try 
        {
            data++;
            Console.WriteLine($"Writing data: {data} (Thread {threadID})");
        } finally 
        {
            rwlock.ReleaseWriterLock();
        }
    }
}