package main

import (
	"fmt"
	"sync"
)

func main() {
	var mu sync.Mutex
	counter := 0

	var wg sync.WaitGroup
	wg.Add(5)

	for range 5 {
		go func() {
			defer wg.Done()
			for range 1000 {
				mu.Lock()
				counter++
				mu.Unlock()
			}
		}()
	}

	wg.Wait()
	fmt.Println("counter akhir:", counter)
}