package main
import (
   "sync"
   "time"
   "math/rand"
   "fmt"
   "sync/atomic"
)
var wait sync.WaitGroup
var count int64
func  increment(s string)  {
   for i :=0;i<10;i++ {
      time.Sleep(time.Duration((rand.Intn(3)))*time.Millisecond)
      atomic.AddInt64(&count,1)
      fmt.Println(s,i,"Count ->",count)
   }
   wait.Done()
}
func main(){
   wait.Add(2)
   go increment("foo: ")
   go increment("bar: ")
   wait.Wait()
   fmt.Println("last count value " ,count)
}

foo:  0 Count -> 1
foo:  1 Count -> 2
bar:  0 Count -> 3
bar:  1 Count -> 4
bar:  2 Count -> 5
foo:  2 Count -> 6
bar:  3 Count -> 7
bar:  4 Count -> 8
bar:  5 Count -> 9
foo:  3 Count -> 10
bar:  6 Count -> 11
bar:  7 Count -> 12
foo:  4 Count -> 13
foo:  5 Count -> 14
bar:  8 Count -> 15
bar:  9 Count -> 16
foo:  6 Count -> 17
foo:  7 Count -> 18
foo:  8 Count -> 19
foo:  9 Count -> 20
last count value  20