What is the difference between WaitGroup and Channel in Go?

Question

Accepted Answer

**WaitGroup** — wait for goroutines to finish. **Channel** — communicate between goroutines.

**sync.WaitGroup:**
- Wait for completion.
- No data transfer.
- Counter-based.

```go
var wg sync.WaitGroup

for i := 0; i < 5; i++ {
    wg.Add(1)
    go func(id int) {
        defer wg.Done()
        fmt.Println("Worker", id)
    }(i)
}

wg.Wait()  // Wait for all
fmt.Println("All done")
```

**Channel:**
- Data transfer.
- Communication.
- Can signal completion.

```go
done := make(chan bool)

go func() {
    fmt.Println("Working...")
    done <- true  // Signal done
}()

<-done  // Wait for signal
fmt.Println("All done")
```

**Key differences:**
- **WaitGroup** — wait only.
- **Channel** — communicate.
- **WaitGroup** — simpler for waiting.
- **Channel** — more flexible.

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