# multithreading

thread is an execution path of a program
we can use multiple threads to perform,
different taks of our program at the same time.
Current thread running is "main" thread
using System.Threading;

## Single Thread
```C#
// single Thread
using System.Threading;

Thread mainThread = Thread.CurrenThread;
mainThread.Name = "Main Thread";
Console.WriteLine(mainThread.Name);
```

### Timer Example

```C#
public static void CountDown()
{
    for (int i = 10; i >=0; i--)
    {
        Console.WriteLine("Timer #1 : " + i + " seconds");
        Thread.Sleep(1000)
    }
    Console.WriteLine("Timer #1 is complete !")
}

public static void CountUp()
{
    for (int i = 0; i >=0; i++)
    {
        Console.WriteLine("Timer #2 : " + i + " seconds");
        Thread.Sleep(1000)
    }
    Console.WriteLine("Timer #2 is complete !")
}
```

```C#
// Main

CountDown();
CountUp();
```

## multiple Thread

```C#
public static void CountDown()
{
    for (int i = 10; i >=0; i--)
    {
        Console.WriteLine("Timer #1 : " + i + " seconds");
        Thread.Sleep(1000)
    }
    Console.WriteLine("Timer #1 is complete !")
}

public static void CountUp()
{
    for (int i = 0; i >=0; i++)
    {
        Console.WriteLine("Timer #2 : " + i + " seconds");
        Thread.Sleep(1000)
    }
    Console.WriteLine("Timer #2 is complete !")
}
```

```C#
// Main

Thread thread1 = new Thread(CountDown);
Thread thread2 = new Thread(CountUp);

// if the function got a parameter
// use a lambda
// Thread thread1 = new Thread(() => CountDown("Thimer #1"));


thread1.start();
thread2.start();

CountDown();
CountUp();
```