Golang中如何通过指针实现数据共享 演示多协程读写同一内存区域

package main

import (
    "fmt"
    "sync"
    "time"
)

type Counter struct {
    mu    sync.Mutex
    count int
}

func (c *Counter) Increment() {
    c.mu.Lock()
    defer c.mu.Unlock()
    c.count++
}

func (c *Counter) Value() int {
    c.mu.Lock()
    defer c.mu.Unlock()
    return c.count
}

func main() {
    counter := Counter{}
    var wg sync.WaitGroup

    for i := 0; i < 1000; i++ {
        wg.Add(1)
        go func() {
            defer wg.Done()
            counter.Increment()
        }()
    }

    wg.Wait()
    fmt.Println("Counter:", counter.Value())
}

package main

import (
    "fmt"
    "sync"
    "time"
)

type Data struct {
    mu sync.RWMutex
    value int
}

func (d *Data) Read() int {
    d.mu.RLock()
    defer d.mu.RUnlock()
    return d.value
}

func (d *Data) Write(newValue int) {
    d.mu.Lock()
    defer d.mu.Unlock()
    d.value = newValue
}

func main() {
    data := Data{value: 0}
    var wg sync.WaitGroup

    // 多个reader
    for i := 0; i < 5; i++ {
        wg.Add(1)
        go func(id int) {
            defer wg.Done()
            for j := 0; j < 5; j++ {
                fmt.Printf("Reader %d: %d\n", id, data.Read())
                time.Sleep(time.Millisecond * 100)
            }
        }(i)
    }

    // 一个writer
    wg.Add(1)
    go func() {
        defer wg.Done()
        for i := 0; i < 3; i++ {
            data.Write(i * 10)
            fmt.Printf("Writer: %d\n", i*10)
            time.Sleep(time.Millisecond * 300)
        }
    }()

    wg.Wait()
}

package main

import (
    "fmt"
    "sync"
)

func main() {
    ch := make(chan int)
    var wg sync.WaitGroup

    wg.Add(1)
    go func() {
        defer wg.Done()
        for i := 0; i < 5; i++ {
            ch <- i
            fmt.Println("Sent:", i)
        }
        close(ch) // 关闭通道，通知接收方没有更多数据
    }()

    wg.Add(1)
    go func() {
        defer wg.Done()
        for num := range ch { // 从通道接收数据，直到通道关闭
            fmt.Println("Received:", num)
        }
    }()

    wg.Wait()
}