// access to shared memory among threads
// controlled using atomics.
// For this program (and many like it) atomics are far
// preferable to locks (faster and less error prone)
//
// The basic idea here is to start a bunch of thread and
// have them all increment a single variable
//
// Author:  gtowell
// Created: August 2022

package main

import (
	"fmt"
	"sync"
	"sync/atomic"
)
var (
	counter int64
)
func main()  {
	var wg sync.WaitGroup
	var threads int64 = 100
	var times int64 = 10000000
	var rz int64
	for rz=0; rz<threads; rz++ {
		wg.Add(1)
		go func(_rr int64) {
			defer wg.Done()
			var th int64
			for th=1; th<=times; th++ {
				atomic.AddInt64(&counter,th)
			}
		}(rz)
	}
	wg.Wait()
	fmt.Printf("summer done   %v\n", counter);	
}