在do表示法中使用id

package main

import (
    "fmt"
    "time"
)

func say(s string) {
    for i := 0; i < 5; i++ {
        time.Sleep(100 * time.Millisecond)
        fmt.Println(s)
    }
}

func main() {
    go say("world") // 启动一个新的goroutine
    say("hello")    // 在主goroutine中执行
}

func worker(done chan bool) {
    fmt.Println("working...")
    time.Sleep(time.Second)
    fmt.Println("finished")
    done <- true
}

func main() {
    done := make(chan bool, 1)
    go worker(done)
    <-done // 等待worker goroutine完成
}

import (
    "fmt"
    "sync"
)

var counter int
var mutex sync.Mutex

func increment() {
    mutex.Lock()
    counter++
    mutex.Unlock()
}

func main() {
    var wg sync.WaitGroup
    for i := 0; i < 1000; i++ {
        wg.Add(1)
        go func() {
            defer wg.Done()
            increment()
        }()
    }
    wg.Wait()
    fmt.Println(counter)
}