Explain panic, recover, and when to use them.

Panic and Recover: • Panic stops normal execution • Deferred functions still run • Recover catches panics in deferred functions • Use for unrecoverable errors • Prefer errors for expected failures Example: func safeDivide(a, b float64) (result float64, err error) { defer func() { if r := recover(); r != nil { err = fmt.Errorf("panic: %v", r) } }() if b == 0 { panic("division by zero") } return a / b, nil } When to use: • Library initialization failures • Impossible conditions • Programming errors (not user errors)