package main

import (
    "fmt"
    "time"
)

func sayHello() {
    for i := 1; i <= 5; i++ {
        fmt.Println("Hello")
        time.Sleep(1 * time.Second)
    }
}

func main() {
    go sayHello() // เรียกใช้ Goroutine

    for i := 1; i <= 5; i++ {
        fmt.Println("World")
        time.Sleep(1 * time.Second)
    }
}

ch := make(chan int) // สร้างช่องสัญญาณที่รับ-ส่งข้อมูลประเภท int

package main

import "fmt"

func main() {
    ch := make(chan string)

    go func() {
        ch <- "Hello from Goroutine" // ส่งข้อมูลเข้า Channel
    }()

    msg := <-ch // รับข้อมูลจาก Channel
    fmt.Println(msg)
}

Hello from Goroutine

package main

import "fmt"

func sum(numbers []int, result chan int) {
    sum := 0
    for _, n := range numbers {
        sum += n
    }
    result <- sum // ส่งผลรวมเข้า Channel
}

func main() {
    numbers := []int{1, 2, 3, 4, 5, 6}

    ch1 := make(chan int)
    ch2 := make(chan int)

    go sum(numbers[:len(numbers)/2], ch1) // ครึ่งแรก
    go sum(numbers[len(numbers)/2:], ch2) // ครึ่งหลัง

    total := <-ch1 + <-ch2 // รวมผลลัพธ์จากทั้งสอง Goroutine
    fmt.Println("Total Sum:", total)
}

Total Sum: 21

package main

import "fmt"

func main() {
    ch := make(chan int, 3)

    ch <- 1
    ch <- 2
    close(ch) // ปิด Channel

    for num := range ch {
        fmt.Println(num)
    }
}

1
2

package main

import (
    "fmt"
    "time"
)

func main() {
    ch1 := make(chan string)
    ch2 := make(chan string)

    go func() {
        time.Sleep(2 * time.Second)
        ch1 <- "Message from ch1"
    }()

    go func() {
        time.Sleep(1 * time.Second)
        ch2 <- "Message from ch2"
    }()

    select {
    case msg1 := <-ch1:
        fmt.Println(msg1)
    case msg2 := <-ch2:
        fmt.Println(msg2)
    }
}

Message from ch2

package main

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

func worker(id int, wg *sync.WaitGroup) {
    defer wg.Done() // แจ้งว่า Goroutine นี้เสร็จแล้ว
    fmt.Printf("Worker %d started\n", id)
    time.Sleep(2 * time.Second)
    fmt.Printf("Worker %d finished\n", id)
}

func main() {
    var wg sync.WaitGroup

    for i := 1; i <= 3; i++ {
        wg.Add(1)
        go worker(i, &wg)
    }

    wg.Wait() // รอจนกว่าทุก Goroutine จะทำงานเสร็จ
    fmt.Println("All workers finished")
}

package main

import (
    "fmt"
    "time"
)

var counter int

func increment() {
    for i := 0; i < 1000; i++ {
        counter++
    }
}

func main() {
    go increment()
    go increment()

    time.Sleep(1 * time.Second)
    fmt.Println("Final Counter:", counter)
}

package main

import (
    "fmt"
    "sync"
)

var (
    counter int
    mu      sync.Mutex
)

func increment() {
    for i := 0; i < 1000; i++ {
        mu.Lock()
        counter++
        mu.Unlock()
    }
}

func main() {
    var wg sync.WaitGroup
    wg.Add(2)

    go func() { defer wg.Done(); increment() }()
    go func() { defer wg.Done(); increment() }()

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