Counter - shared variable

examples/counter/counter.go

package main

import (
    "fmt"
    "sync"
)

var counter int
var wg sync.WaitGroup

func count(n int) {
    for i := 0; i < n; i++ {
        counter++
    }
    wg.Done()
}

func main() {
    for j := 0; j < 3; j++ {
        wg.Add(1)
        go count(10000)
    }
    wg.Wait()

    fmt.Println(counter)
}