# finally

Bundan avvalgi darslarimizda try/catch bloki haqida yaxshigina ma’lumotlarni qo’lga kiritigansiz degan umidda ushbu bloklarning finalini ta’minlovchi finally haqida so’z yuritamiz. Dasturlar ba’zida istisno holatlari bilan yakunlangan bo’lishi mumkin, ya’ni dastur tanasining **try { ... }** bloki bajarilmasdan aksincha, dastur **catch { ... }** bloki ichida yakunlangan. Ammo ba’zida dastur xatolik holatiga tushguniga qadar biror yopilishi kerak bo’lgan fayl yoki tarmoqni ochgan bo’lishi mumkin. Bunday ochilgan tarmoq va fayllarni yopish uchun **finally { ... }** blokidan foydalaniladi.

{% hint style="info" %}
**finally** bloki har qanday istisno holati (catch) yoki try bloki bajarilishidan qat’iy nazar bajariladi.
{% endhint %}

"Sizlar nima qilsangiz ham men baribir so’ngida o’z so’zimni aytaman" shiori ostida ish ko’ruvchi blokni amaliy misollarda qaraymiz:

```csharp
try
{
    int a = 0;
    int b = 5;
    Console.WriteLine(b/a);
}

catch(DivideByZeroException)
{
    Console.WriteLine("0 ga bo'lish mumkin emas !");
}

finally
{
    Console.WriteLine("Dastur ishlashi tugallandi.");
} 
```

Yuqoridagi holatda dasturning istisno holati bajarilgach, finally bloki ichidagi kod o’z ishini boshlaydi. Agar o’zgaruvchilarning qiymatlarini misol uchun a = 2, b = 4 tarzida o’zgartirsak, u holda, dasturning catch bloki bajarilmaydi, lekin so’ngida baribir finally bloki ichidagi kod bajarilishini ko’rish mumkin.

Endi yana bir misolni qaraymiz. Faraz qilaylik, ma’lum katalogdagi fayldagi ma’lumotlarni boshqa faylning ma’lumotlariga qo’shish kerak:

```csharp
StreamReader reader = null;
StreamWriter writer = null;
try
{
    reader = new StreamReader(File.Open(@"C:\Users\Public\Documents\file1.txt", FileMode.Open));
    writer = new StreamWriter(File.Open(@"C:\Users\Public\Documents\file2.txt", FileMode.Append, FileAccess.Write));
    while (reader.Peek() != -1)
    {
        writer.WriteLine(reader.ReadLine());
    }

}

catch(Exception ex)
{
     Console.WriteLine(ex);
}
```

Yuqoridagi holatda *file1.txt* faylining ma’lumotlari *file2.txt* ga qo’shilmoqda. Agar *file1.txt* dagi ma’lumotlarni o’qishda yoki *file2.txt* ga ma’lumotlarni yozishda qandaydir xatolik ro’y bersa, dasturning catch bloki bajariladi va xatolik to’g’risida xabar qilinadi. Lekin shuni unutmaslik kerak-ki, dastur catch holatiga tushganda ikkala fayllarning ham holati ochiq holda. Endi ushbu dasturga finally bloki ichida bu ikkala faylni ham yopuvchi kodni yozish eng to’g’ri qaror:

```csharp
StreamReader reader = null;
StreamWriter writer = null;
try
{
    reader = new StreamReader(File.Open(@"C:\Users\Public\Documents\file1.txt", FileMode.Open));
    writer = new StreamWriter(File.Open(@"C:\Users\Public\Documents\file2.txt", FileMode.Append, FileAccess.Write));
    while (reader.Peek() != -1)
    {
        writer.WriteLine(reader.ReadLine());
    }
}

catch(Exception ex)
{
    Console.WriteLine(ex);
}

finally
{
    if(reader != null)
    {
        reader.Close();
    }

    if(writer != null)
    {
        writer.Close();
    }
}

Console.ReadKey(); 
```