concurrency.go

package main

import (
	"fmt"
	"time"
)

func main() {
	x := make([]chan bool, 10)
	for i := 0; i < 10; i++ {
		x[i] = make(chan bool)
		go func(n int) {
			dur, _ := time.ParseDuration(fmt.Sprintf("%ds", 10-n))
			time.Sleep(dur)
			fmt.Printf("Hello %d\n", n+1)
			x[n] <- true
		}(i)
	}

	for i := 0; i < 10; i++ {
		<-x[i]
	}

}

// Outputs:
/*
Hello 10
Hello 9
Hello 8
Hello 7
Hello 6
Hello 5
Hello 4
Hello 3
Hello 2
Hello 1
*/