string? optionalText = null; // This is allowed in C# 8.0
string requiredText = "Hello, world!";
```

### **2. Async Streams**
Introduces asynchronous streams using the `await foreach` syntax, enabling asynchronous iteration over collections.

```csharp
async IAsyncEnumerable<int> GetDataAsync()
{
    for (int i = 0; i < 10; i++)
    {
        await Task.Delay(1000);
        yield return i;
    }
}

await foreach (var number in GetDataAsync())
{
    Console.WriteLine(number);
}
```

### **3. Default Interface Methods**
Allows default implementations of methods in interfaces, which can help to extend interfaces without breaking existing code.

```csharp
public interface ICar
{
    void Drive();
    void Stop() => Console.WriteLine("Default Stop");
}
```

### **4. Pattern Matching Enhancements**
Extends pattern matching capabilities with recursive patterns and switch expressions, making code more concise and expressive.

```csharp
public static decimal CalculateDiscount(Product product) =>
    product switch
    {
        { Price: > 1000 } => 0.1m,
        { OnSale: true } => 0.2m,
        _ => 0.0m
    };

```

### **5. Using Declarations**
Simplifies the syntax for using statements, reducing the scope of resource cleanup[_{{{CITATION{{{_3{New Features of .NET 8 - C# Corner](https://www.c-sharpcorner.com/article/new-features-of-net-8/).

```csharp
using var file = new StreamWriter("path_to_file.txt");
// file is automatically disposed at the end of the scope
```

### **6. Indices and Ranges**
Introduces a more readable and flexible way to access elements in arrays and spans using indices and ranges[_{{{CITATION{{{_1{C# 8 New Features - Dot Net Tutorials](https://dotnettutorials.net/lesson/csharp-8-new-features/).

```csharp
int[] numbers = { 0, 1, 2, 3, 4, 5 };
int lastElement = numbers[^1]; // 5
int[] firstTwo = numbers[..2]; // { 0, 1 }
int[] middle = numbers[1..4]; // { 1, 2, 3 }
```

### **7. Null-Coalescing Assignment**
Adds a new operator `??=`, which assigns a value to a variable if it is currently null[_{{{CITATION{{{_1{C# 8 New Features - Dot Net Tutorials](https://dotnettutorials.net/lesson/csharp-8-new-features/).

```csharp
string? name = null;
name ??= "Default Name"; // name is now "Default Name"
```

### **8. Stackalloc in Nested Expressions**
Allows more efficient memory management by using stack-allocated memory in nested expressions[_{{{CITATION{{{_1{C# 8 New Features - Dot Net Tutorials](https://dotnettutorials.net/lesson/csharp-8-new-features/).

```csharp
Span<int> numbers = stackalloc[] { 1, 2, 3, 4, 5 };
```

### **9. Enhancement of Interpolated Verbatim Strings**
Combines interpolated strings and verbatim strings for cleaner multi-line formatting[_{{{CITATION{{{_1{C# 8 New Features - Dot Net Tutorials](https://dotnettutorials.net/lesson/csharp-8-new-features/).

```csharp
var text = $@"This is 
              a multi-line 
              interpolated string: {variable}";
```

C# 8.0 packed a lot of powerful features that help make the developer's life easier, more efficient, and more enjoyable. If you have any specific questions or need examples on any of these features, feel free to ask!