C# Interview Question #64

What is the difference between synchronous and asynchronous programming?

Async/Await, Tasks & Multithreading Mid-Level Intermediate

Quick Interview Answer

Synchronous code normally waits for each operation to complete before continuing. If a thread performs blocking I/O, that thread remains occupied while waiting.

Detailed Explanation

Synchronous code normally waits for each operation to complete before continuing. If a thread performs blocking I/O, that thread remains occupied while waiting.

Asynchronous code can suspend the current operation while waiting and allow the thread to perform other work. This is particularly beneficial for I/O-bound workloads such as database queries, HTTP requests, and file operations.

Asynchronous programming does not necessarily make an individual operation faster. Its major benefit in server applications is better resource utilization and scalability under concurrent workloads.

Code Example

// Synchronous
var products = _context.Products.ToList();

// Asynchronous
var productsAsync = await _context.Products.ToListAsync();