What is the difference between Stopwatch and Timer?

Question

Accepted Answer

**Stopwatch** — measure elapsed time. **Timer** — periodic callback.

**Stopwatch:**
- Measure duration.
- High resolution.
- Benchmarking.

**Timer:**
- Periodic execution.
- Callback.
- Scheduled.

```csharp
// Stopwatch
var sw = Stopwatch.StartNew();
DoWork();
sw.Stop();
Console.WriteLine($"Elapsed: {sw.ElapsedMilliseconds}ms");

// Timer
var timer = new Timer(_ => Console.WriteLine("Tick"),
    null, TimeSpan.Zero, TimeSpan.FromSeconds(1));
```

**Key:** Stopwatch for measurement, Timer for scheduling.

C#: What is the difference between Stopwatch and Timer?