package main

import (
	"fmt"
	"sync"
)

var x = 0

func main() {
	var w sync.WaitGroup
	var m sync.Mutex

	numRunners := 2000

	w.Add(numRunners)

	for i := 0; i < numRunners; i++ {
		go increment(&w, &m)
	}

	w.Wait()

	fmt.Println("Final value of x: ", x)
}

func increment(wg *sync.WaitGroup, m sync.Locker) {
	m.Lock()
	{
		x = x + 1
	}
	m.Unlock()

	wg.Done()
}