What is the difference between Async and Await in C#?

 In C#, async and await are keywords used in asynchronous programming to simplify the process of executing long-running operations asynchronously without blocking the main thread.

async is used to mark a method as an asynchronous method, which can perform long-running operations without blocking the calling thread. The method returns a Task or Task<T> object that represents the ongoing operation.

await is used to indicate that the calling code should wait asynchronously for the completion of a Task<T> or Task operation. When the await keyword is encountered in the code, the compiler generates code that automatically schedules the continuation of the method after the asynchronous operation completes.

In simpler terms, async is used to define a method as asynchronous, and await is used to wait for the result of an asynchronous operation.

Here's an example:

csharp
async Task<string> GetDataAsync() 
{ 
// perform some long-running operation 
await Task.Delay(5000); 
// wait for 5 seconds 
return "data"; 
} 
async Task DoSomethingAsync() 
{ 
// call GetDataAsync and wait for the result 
string data = await GetDataAsync();

   // do something with the data
   Console.WriteLine(data); 
}

In this example, GetDataAsync is marked as async, which allows it to perform a long-running operation (in this case, a 5-second delay) without blocking the calling thread. The method returns a Task<string> object that represents the ongoing operation.

DoSomethingAsync is also marked as async and calls GetDataAsync using the await keyword. The code after the await statement is automatically scheduled to run after the completion of the asynchronous operation.

Note that the use of async and await can significantly simplify asynchronous programming, but it's important to use them correctly to avoid introducing bugs or performance issues in your code.