110 lines
5.0 KiB
C#
110 lines
5.0 KiB
C#
using System;
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using System.Text;
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using System.Threading.Tasks;
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namespace Multithreading
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{
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internal static class Program
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{
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private static readonly object _fileLock = new object();
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public static void Main(string[] args)
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{
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Console.WriteLine("Program started");
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// int[] numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
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// Task[] tasks = new Task[100];
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// Random random = new Random();
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// for (int i = 0; i < tasks.Length; i++)
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// {
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// tasks[i] = Task.Run(() =>
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// {
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// for (int j = 0; j < numbers.Length; j++)
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// {
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// Console.WriteLine($"Before Thread Id: {Thread.CurrentThread.ManagedThreadId}, number({j}): {numbers[j]}");
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//
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// Thread.Sleep(random.Next(0, 1000));
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//
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// // not thread-safe
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// // int oldValue = numbers[j];
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// // int newValue = oldValue * random.Next(10);
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// // numbers[j] = newValue;
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// // Thread.Sleep(random.Next(0, 1000));
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// // Console.WriteLine($"After Thread Id: {Thread.CurrentThread.ManagedThreadId}, number({j}): {numbers[j]} / oldValue: {oldValue} / newValue: {newValue}");
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//
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// // making this thread-safe
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// // option 1: lock
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// lock (numbers)
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// {
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// int oldValue = numbers[j];
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// int newValue = oldValue * random.Next(10);
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// numbers[j] = newValue;
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// Thread.Sleep(random.Next(0, 1000));
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// Console.WriteLine($"After Thread Id: {Thread.CurrentThread.ManagedThreadId}, number({j}): {numbers[j]} / oldValue: {oldValue} / newValue: {newValue}");
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// }
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//
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// // option 2: use concurrent collections
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// // https://learn.microsoft.com/en-us/dotnet/standard/collections/thread-safe/
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//
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// // option 3: use chunks to have no overlapping
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//
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// }
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// });
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// }
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// Dictionary<int, string> dictionary = new Dictionary<int, string>();
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// Task[] tasks = new Task[1000];
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// Random random = new Random();
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// for (int i = 0; i < tasks.Length; i++)
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// {
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// tasks[i] = Task.Run(() =>
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// {
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// lock (dictionary) // one option, another option is to use ConcurrentDictionary
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// {
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// int key = random.Next();
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// if (!dictionary.ContainsKey(key))
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// {
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// // dictionary[key] = $"Thread Id: {Thread.CurrentThread.ManagedThreadId}, number({key}): {random.Next(10)}";
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// dictionary.TryAdd(key, $"Thread Id: {Thread.CurrentThread.ManagedThreadId}, number({key}): {random.Next(10)}");
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// }
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// }
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// });
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// }
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Task[] tasks = new Task[100];
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Random random = new Random();
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File.Delete("output.txt");
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for (int i = 0; i < tasks.Length; i++)
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{
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tasks[i] = Task.Run(() =>
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{
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// not thread-safe
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// File.AppendAllText("output.txt", $"Thread Id: {Thread.CurrentThread.ManagedThreadId}, number: {random.Next(10)}\n");
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// FileStream fs = File.OpenWrite("output.txt");
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// FileStream fs = File.Open("output.txt", FileMode.Append, FileAccess.Write, FileShare.ReadWrite);
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// string s = $"{Thread.CurrentThread.ManagedThreadId}, number: {random.Next(10)}\n";
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// byte[] bytes = Encoding.UTF8.GetBytes(s);
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// fs.Write(bytes, 0, bytes.Length);
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// fs.Close();
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// fs.Dispose();
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// thread-safe
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lock (_fileLock)
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{
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FileStream fs = File.Open("output.txt", FileMode.Append, FileAccess.Write, FileShare.ReadWrite);
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string s = $"{Thread.CurrentThread.ManagedThreadId}, number: {random.Next(10)}\n";
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byte[] bytes = Encoding.UTF8.GetBytes(s);
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fs.Write(bytes, 0, bytes.Length);
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fs.Close();
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fs.Dispose();
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}
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});
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}
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Task.WaitAll(tasks);
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Console.WriteLine("Program ended");
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}
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}
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} |