package main

import (
	"fmt"
	"sync"
	"sync/atomic"
)

func main() {
	var counter int64
	var wg sync.WaitGroup
	const goroutines, increments = 10, 10000

	wg.Add(goroutines)
	for i := 0; i < goroutines; i++ {
		go func() {
			defer wg.Done()
			for j := 0; j < increments; j++ {
				for {
					old := atomic.LoadInt64(&counter)
					if atomic.CompareAndSwapInt64(&counter, old, old+1) {
						break // 成功则退出重试循环
					}
					// 失败：其他 goroutine 已修改，重试
				}
			}
		}()
	}
	wg.Wait()
	fmt.Printf("✅ 最终计数值: %d (期望: %d)\n", counter, goroutines*increments)
}